diff --git a/include/display.h b/include/display.h
index abede528d..9da288d67 100644
--- a/include/display.h
+++ b/include/display.h
@@ -215,13 +215,13 @@
 
 #define display_self() \
     show_glyph(u.ux, u.uy,                                                  \
-           maybe_display_usteed((youmonst.m_ap_type == M_AP_NOTHING)        \
+           maybe_display_usteed((U_AP_TYPE == M_AP_NOTHING)                 \
                                 ? hero_glyph                                \
-                                : (youmonst.m_ap_type == M_AP_FURNITURE)    \
+                                : (U_AP_TYPE == M_AP_FURNITURE)             \
                                   ? cmap_to_glyph(youmonst.mappearance)     \
-                                  : (youmonst.m_ap_type == M_AP_OBJECT)     \
+                                  : (U_AP_TYPE == M_AP_OBJECT)              \
                                     ? objnum_to_glyph(youmonst.mappearance) \
-                                    /* else M_AP_MONSTER */                 \
+                                    /* else U_AP_TYPE == M_AP_MONSTER */    \
                                     : monnum_to_glyph(youmonst.mappearance)))
 
 /*
diff --git a/include/monst.h b/include/monst.h
index dde983205..9a0b4f243 100644
--- a/include/monst.h
+++ b/include/monst.h
@@ -47,9 +47,16 @@ enum m_ap_types {
     M_AP_NOTHING   = 0, /* mappearance unused--monster appears as itself */
     M_AP_FURNITURE = 1, /* stairs, a door, an altar, etc. */
     M_AP_OBJECT    = 2, /* an object */
-    M_AP_MONSTER   = 3  /* a monster; mostly used for cloned Wizard */
+    M_AP_MONSTER   = 3, /* a monster; mostly used for cloned Wizard */
 };
 
+#define M_AP_TYPMASK  0x7
+#define M_AP_F_DKNOWN 0x8
+#define U_AP_TYPE (youmonst.m_ap_type & M_AP_TYPMASK)
+#define U_AP_FLAG (youmonst.m_ap_type & ~M_AP_TYPMASK)
+#define M_AP_TYPE(m) ((m)->m_ap_type & M_AP_TYPMASK)
+#define M_AP_FLAG(m) ((m)->m_ap_type & ~M_AP_TYPMASK)
+
 struct monst {
     struct monst *nmon;
     struct permonst *data;
@@ -170,15 +177,15 @@ struct monst {
 /* mimic appearances that block vision/light */
 #define is_lightblocker_mappear(mon)                       \
     (is_obj_mappear(mon, BOULDER)                          \
-     || ((mon)->m_ap_type == M_AP_FURNITURE                \
+     || (M_AP_TYPE(mon) == M_AP_FURNITURE                    \
          && ((mon)->mappearance == S_hcdoor                \
              || (mon)->mappearance == S_vcdoor             \
              || (mon)->mappearance < S_ndoor /* = walls */ \
              || (mon)->mappearance == S_tree)))
-#define is_door_mappear(mon) ((mon)->m_ap_type == M_AP_FURNITURE \
+#define is_door_mappear(mon) (M_AP_TYPE(mon) == M_AP_FURNITURE   \
                               && ((mon)->mappearance == S_hcdoor \
                                   || (mon)->mappearance == S_vcdoor))
-#define is_obj_mappear(mon,otyp) ((mon)->m_ap_type == M_AP_OBJECT \
+#define is_obj_mappear(mon,otyp) (M_AP_TYPE(mon) == M_AP_OBJECT \
                                   && (mon)->mappearance == (otyp))
 
 #endif /* MONST_H */
diff --git a/src/apply.c b/src/apply.c
index fdb5fa4a1..998d4ddec 100644
--- a/src/apply.c
+++ b/src/apply.c
@@ -384,7 +384,7 @@ register struct obj *obj;
         } else if (mtmp->mappearance) {
             const char *what = "thing";
 
-            switch (mtmp->m_ap_type) {
+            switch (M_AP_TYPE(mtmp)) {
             case M_AP_OBJECT:
                 what = simple_typename(mtmp->mappearance);
                 break;
@@ -486,7 +486,7 @@ struct obj *obj;
                 }
                 /* mimic must be revealed before we know whether it
                    actually moves because line-of-sight may change */
-                if (mtmp->m_ap_type)
+                if (M_AP_TYPE(mtmp))
                     seemimic(mtmp);
                 omx = mtmp->mx, omy = mtmp->my;
                 mnexto(mtmp);
@@ -2109,7 +2109,7 @@ long timeout;
         and_vanish[0] = '\0';
         if ((mtmp->minvis && !See_invisible)
             || (mtmp->data->mlet == S_MIMIC
-                && mtmp->m_ap_type != M_AP_NOTHING))
+                && M_AP_TYPE(mtmp) != M_AP_NOTHING))
             suppress_see = TRUE;
 
         if (mtmp->mundetected) {
@@ -2840,7 +2840,7 @@ struct obj *obj;
             }
             wakeup(mtmp, TRUE);
         } else {
-            if (mtmp->m_ap_type && !Protection_from_shape_changers
+            if (M_AP_TYPE(mtmp) && !Protection_from_shape_changers
                 && !sensemon(mtmp))
                 stumble_onto_mimic(mtmp);
             else
diff --git a/src/cmd.c b/src/cmd.c
index c3166bd6a..34444a483 100644
--- a/src/cmd.c
+++ b/src/cmd.c
@@ -2272,7 +2272,7 @@ int final;
                   : surface(u.ux, u.uy)); /* catchall; shouldn't happen */
         you_are(buf, from_what(WWALKING));
     }
-    if (Upolyd && (u.uundetected || youmonst.m_ap_type != M_AP_NOTHING))
+    if (Upolyd && (u.uundetected || U_AP_TYPE != M_AP_NOTHING))
         youhiding(TRUE, final);
 
     /* internal troubles, mostly in the order that prayer ranks them */
@@ -3094,16 +3094,16 @@ int msgflag;          /* for variant message phrasing */
     char *bp, buf[BUFSZ];
 
     Strcpy(buf, "hiding");
-    if (youmonst.m_ap_type != M_AP_NOTHING) {
+    if (U_AP_TYPE != M_AP_NOTHING) {
         /* mimic; hero is only able to mimic a strange object or gold
            or hallucinatory alternative to gold, so we skip the details
            for the hypothetical furniture and monster cases */
         bp = eos(strcpy(buf, "mimicking"));
-        if (youmonst.m_ap_type == M_AP_OBJECT) {
+        if (U_AP_TYPE == M_AP_OBJECT) {
             Sprintf(bp, " %s", an(simple_typename(youmonst.mappearance)));
-        } else if (youmonst.m_ap_type == M_AP_FURNITURE) {
+        } else if (U_AP_TYPE == M_AP_FURNITURE) {
             Strcpy(bp, " something");
-        } else if (youmonst.m_ap_type == M_AP_MONSTER) {
+        } else if (U_AP_TYPE == M_AP_MONSTER) {
             Strcpy(bp, " someone");
         } else {
             ; /* something unexpected; leave 'buf' as-is */
diff --git a/src/detect.c b/src/detect.c
index 3a25d45fb..45271687d 100644
--- a/src/detect.c
+++ b/src/detect.c
@@ -655,7 +655,7 @@ int class;            /* an object class, 0 for all */
             if (do_dknown)
                 do_dknown_of(obj);
         }
-        if ((is_cursed && mtmp->m_ap_type == M_AP_OBJECT
+        if ((is_cursed && M_AP_TYPE(mtmp) == M_AP_OBJECT
              && (!class || class == objects[mtmp->mappearance].oc_class))
             || (findgold(mtmp->minvent) && (!class || class == COIN_CLASS))) {
             ct++;
@@ -730,7 +730,7 @@ int class;            /* an object class, 0 for all */
                 break;
             }
         /* Allow a mimic to override the detected objects it is carrying. */
-        if (is_cursed && mtmp->m_ap_type == M_AP_OBJECT
+        if (is_cursed && M_AP_TYPE(mtmp) == M_AP_OBJECT
             && (!class || class == objects[mtmp->mappearance].oc_class)) {
             struct obj temp;
 
@@ -1469,7 +1469,7 @@ genericptr_t num;
             (*(int *) num)++;
         }
     } else if ((mtmp = m_at(zx, zy)) != 0) {
-        if (mtmp->m_ap_type) {
+        if (M_AP_TYPE(mtmp)) {
             seemimic(mtmp);
             (*(int *) num)++;
         }
@@ -1633,7 +1633,7 @@ boolean via_warning;
     if (via_warning && !warning_of(mtmp))
         return -1;
 
-    if (mtmp->m_ap_type) {
+    if (M_AP_TYPE(mtmp)) {
         seemimic(mtmp);
         found_something = TRUE;
     } else if (!canspotmon(mtmp)) {
@@ -1862,7 +1862,7 @@ int default_glyph, which_subset;
                 /* look for a mimic here posing as furniture;
                    if we don't find one, we'll have to fake it */
                 if ((mtmp = m_at(x, y)) != 0
-                    && mtmp->m_ap_type == M_AP_FURNITURE) {
+                    && M_AP_TYPE(mtmp) == M_AP_FURNITURE) {
                     glyph = cmap_to_glyph(mtmp->mappearance);
                 } else {
                     /* we have a topology type but we want a screen
diff --git a/src/display.c b/src/display.c
index d8abb384e..e44793895 100644
--- a/src/display.c
+++ b/src/display.c
@@ -377,7 +377,7 @@ int sightflags;             /* 1 if the monster is physically seen;
                                2 if detected using Detect_monsters */
 xchar worm_tail;            /* mon is actually a worm tail */
 {
-    boolean mon_mimic = (mon->m_ap_type != M_AP_NOTHING);
+    boolean mon_mimic = (M_AP_TYPE(mon) != M_AP_NOTHING);
     int sensed = (mon_mimic && (Protection_from_shape_changers
                                 || sensemon(mon)));
     /*
@@ -388,7 +388,7 @@ xchar worm_tail;            /* mon is actually a worm tail */
      */
 
     if (mon_mimic && (sightflags == PHYSICALLY_SEEN)) {
-        switch (mon->m_ap_type) {
+        switch (M_AP_TYPE(mon)) {
         default:
             impossible("display_monster:  bad m_ap_type value [ = %d ]",
                        (int) mon->m_ap_type);
diff --git a/src/do_name.c b/src/do_name.c
index 4f6bdbebd..6dd8d5a1e 100644
--- a/src/do_name.c
+++ b/src/do_name.c
@@ -1149,8 +1149,8 @@ do_mname()
     if (!mtmp
         || (!sensemon(mtmp)
             && (!(cansee(cx, cy) || see_with_infrared(mtmp))
-                || mtmp->mundetected || mtmp->m_ap_type == M_AP_FURNITURE
-                || mtmp->m_ap_type == M_AP_OBJECT
+                || mtmp->mundetected || M_AP_TYPE(mtmp) == M_AP_FURNITURE
+                || M_AP_TYPE(mtmp) == M_AP_OBJECT
                 || (mtmp->minvis && !See_invisible)))) {
         pline("I see no monster there.");
         return;
diff --git a/src/dogmove.c b/src/dogmove.c
index 604877103..552da454b 100644
--- a/src/dogmove.c
+++ b/src/dogmove.c
@@ -1361,7 +1361,7 @@ finish_meating(mtmp)
 struct monst *mtmp;
 {
     mtmp->meating = 0;
-    if (mtmp->m_ap_type && mtmp->mappearance && mtmp->cham == NON_PM) {
+    if (M_AP_TYPE(mtmp) && mtmp->mappearance && mtmp->cham == NON_PM) {
         /* was eating a mimic and now appearance needs resetting */
         mtmp->m_ap_type = 0;
         mtmp->mappearance = 0;
@@ -1415,15 +1415,15 @@ struct monst *mtmp;
         newsym(mtmp->mx, mtmp->my);
         You("%s %s %sappear%s where %s was!",
             cansee(mtmp->mx, mtmp->my) ? "see" : "sense that",
-            (mtmp->m_ap_type == M_AP_FURNITURE)
+            (M_AP_TYPE(mtmp) == M_AP_FURNITURE)
                 ? an(defsyms[mtmp->mappearance].explanation)
-                : (mtmp->m_ap_type == M_AP_OBJECT
+                : (M_AP_TYPE(mtmp) == M_AP_OBJECT
                    && OBJ_DESCR(objects[mtmp->mappearance]))
                       ? an(OBJ_DESCR(objects[mtmp->mappearance]))
-                      : (mtmp->m_ap_type == M_AP_OBJECT
+                      : (M_AP_TYPE(mtmp) == M_AP_OBJECT
                          && OBJ_NAME(objects[mtmp->mappearance]))
                             ? an(OBJ_NAME(objects[mtmp->mappearance]))
-                            : (mtmp->m_ap_type == M_AP_MONSTER)
+                            : (M_AP_TYPE(mtmp) == M_AP_MONSTER)
                                   ? an(mons[mtmp->mappearance].mname)
                                   : something,
             cansee(mtmp->mx, mtmp->my) ? "" : "has ",
diff --git a/src/dokick.c b/src/dokick.c
index e06bc285f..55df097e5 100644
--- a/src/dokick.c
+++ b/src/dokick.c
@@ -63,7 +63,7 @@ boolean clumsy;
         return;
     }
 
-    if (mon->m_ap_type)
+    if (M_AP_TYPE(mon))
         seemimic(mon);
 
     check_caitiff(mon);
@@ -166,8 +166,8 @@ xchar x, y;
     /* reveal hidden target even if kick ends up missing (note: being
        hidden doesn't affect chance to hit so neither does this reveal) */
     if (mon->mundetected
-        || (mon->m_ap_type && mon->m_ap_type != M_AP_MONSTER)) {
-        if (mon->m_ap_type)
+        || (M_AP_TYPE(mon) && M_AP_TYPE(mon) != M_AP_MONSTER)) {
+        if (M_AP_TYPE(mon))
             seemimic(mon);
         mon->mundetected = 0;
         if (!canspotmon(mon))
diff --git a/src/dothrow.c b/src/dothrow.c
index 7a83cdd33..1da7d0dca 100644
--- a/src/dothrow.c
+++ b/src/dothrow.c
@@ -1487,7 +1487,7 @@ boolean maybe_wakeup;
        An attentive player will still notice that this is different from
        an arrow just landing short of any target (no message in that case),
        so will realize that there is a valid target here anyway. */
-    if (!canseemon(mon) || (mon->m_ap_type && mon->m_ap_type != M_AP_MONSTER))
+    if (!canseemon(mon) || (M_AP_TYPE(mon) && M_AP_TYPE(mon) != M_AP_MONSTER))
         pline("%s %s.", The(missile), otense(obj, "miss"));
     else
         miss(missile, mon);
diff --git a/src/dungeon.c b/src/dungeon.c
index 10ae01277..08722645b 100644
--- a/src/dungeon.c
+++ b/src/dungeon.c
@@ -2516,7 +2516,7 @@ recalc_mapseen()
                 if (ltyp == DRAWBRIDGE_UP)
                     ltyp = db_under_typ(levl[x][y].drawbridgemask);
                 if ((mtmp = m_at(x, y)) != 0
-                    && mtmp->m_ap_type == M_AP_FURNITURE && canseemon(mtmp))
+                    && M_AP_TYPE(mtmp) == M_AP_FURNITURE && canseemon(mtmp))
                     ltyp = cmap_to_type(mtmp->mappearance);
                 lastseentyp[x][y] = ltyp;
             }
diff --git a/src/eat.c b/src/eat.c
index 94a86568a..4dd3a0a31 100644
--- a/src/eat.c
+++ b/src/eat.c
@@ -161,7 +161,7 @@ eatmdone(VOID_ARGS)
         free((genericptr_t) eatmbuf), eatmbuf = 0;
     }
     /* update display */
-    if (youmonst.m_ap_type) {
+    if (U_AP_TYPE) {
         youmonst.m_ap_type = M_AP_NOTHING;
         newsym(u.ux, u.uy);
     }
diff --git a/src/end.c b/src/end.c
index 080fb729c..73860ace4 100644
--- a/src/end.c
+++ b/src/end.c
@@ -421,7 +421,7 @@ int how;
                                    ? &mons[mtmp->cham]
                                    : mptr);
     boolean distorted = (boolean) (Hallucination && canspotmon(mtmp)),
-            mimicker = (mtmp->m_ap_type == M_AP_MONSTER),
+            mimicker = (M_AP_TYPE(mtmp) == M_AP_MONSTER),
             imitator = (mptr != champtr || mimicker);
 
     You((how == STONING) ? "turn to stone..." : "die...");
diff --git a/src/hack.c b/src/hack.c
index ddb4a5f05..d84dd353d 100644
--- a/src/hack.c
+++ b/src/hack.c
@@ -1533,8 +1533,8 @@ domove_core()
             /* It's fine to displace pets, though */
             /* We should never get here if forcefight */
             if (context.run && ((!Blind && mon_visible(mtmp)
-                                 && ((mtmp->m_ap_type != M_AP_FURNITURE
-                                      && mtmp->m_ap_type != M_AP_OBJECT)
+                                 && ((M_AP_TYPE(mtmp) != M_AP_FURNITURE
+                                      && M_AP_TYPE(mtmp) != M_AP_OBJECT)
                                      || Protection_from_shape_changers))
                                 || sensemon(mtmp))) {
                 nomul(0);
@@ -1574,7 +1574,7 @@ domove_core()
          */
         if (context.nopick && !context.travel
             && (canspotmon(mtmp) || glyph_is_invisible(levl[x][y].glyph))) {
-            if (mtmp->m_ap_type && !Protection_from_shape_changers
+            if (M_AP_TYPE(mtmp) && !Protection_from_shape_changers
                 && !sensemon(mtmp))
                 stumble_onto_mimic(mtmp);
             else if (mtmp->mpeaceful && !Hallucination)
@@ -1762,7 +1762,7 @@ domove_core()
            cancel the swap below (we can ignore steed mx,my here) */
         u.ux = u.ux0, u.uy = u.uy0;
         mtmp->mundetected = 0;
-        if (mtmp->m_ap_type)
+        if (M_AP_TYPE(mtmp))
             seemimic(mtmp);
         else if (!mtmp->mtame)
             newsym(mtmp->mx, mtmp->my);
@@ -1866,8 +1866,8 @@ domove_core()
      * imitating something that doesn't move.  We could extend this
      * to non-moving monsters...
      */
-    if ((u.dx || u.dy) && (youmonst.m_ap_type == M_AP_OBJECT
-                           || youmonst.m_ap_type == M_AP_FURNITURE))
+    if ((u.dx || u.dy) && (U_AP_TYPE == M_AP_OBJECT
+                           || U_AP_TYPE == M_AP_FURNITURE))
         youmonst.m_ap_type = M_AP_NOTHING;
 
     check_leash(u.ux0, u.uy0);
@@ -2655,8 +2655,8 @@ lookaround()
                 continue;
 
             if ((mtmp = m_at(x, y)) != 0
-                && mtmp->m_ap_type != M_AP_FURNITURE
-                && mtmp->m_ap_type != M_AP_OBJECT
+                && M_AP_TYPE(mtmp) != M_AP_FURNITURE
+                && M_AP_TYPE(mtmp) != M_AP_OBJECT
                 && (!mtmp->minvis || See_invisible) && !mtmp->mundetected) {
                 if ((context.run != 1 && !mtmp->mtame)
                     || (x == u.ux + u.dx && y == u.uy + u.dy
@@ -2838,8 +2838,8 @@ monster_nearby()
         for (y = u.uy - 1; y <= u.uy + 1; y++) {
             if (!isok(x, y) || (x == u.ux && y == u.uy))
                 continue;
-            if ((mtmp = m_at(x, y)) && mtmp->m_ap_type != M_AP_FURNITURE
-                && mtmp->m_ap_type != M_AP_OBJECT
+            if ((mtmp = m_at(x, y)) && M_AP_TYPE(mtmp) != M_AP_FURNITURE
+                && M_AP_TYPE(mtmp) != M_AP_OBJECT
                 && (!mtmp->mpeaceful || Hallucination)
                 && (!is_hider(mtmp->data) || !mtmp->mundetected)
                 && !noattacks(mtmp->data) && mtmp->mcanmove
diff --git a/src/lock.c b/src/lock.c
index 3e2337351..270ab1866 100644
--- a/src/lock.c
+++ b/src/lock.c
@@ -453,8 +453,8 @@ struct obj *pick;
 
         door = &levl[cc.x][cc.y];
         mtmp = m_at(cc.x, cc.y);
-        if (mtmp && canseemon(mtmp) && mtmp->m_ap_type != M_AP_FURNITURE
-            && mtmp->m_ap_type != M_AP_OBJECT) {
+        if (mtmp && canseemon(mtmp) && M_AP_TYPE(mtmp) != M_AP_FURNITURE
+            && M_AP_TYPE(mtmp) != M_AP_OBJECT) {
             if (picktyp == CREDIT_CARD
                 && (mtmp->isshk || mtmp->data == &mons[PM_ORACLE]))
                 verbalize("No checks, no credit, no problem.");
@@ -745,8 +745,8 @@ boolean quietly;
 {
     register struct monst *mtmp = m_at(x, y);
 
-    if (mtmp && mtmp->m_ap_type != M_AP_FURNITURE) {
-        if (mtmp->m_ap_type == M_AP_OBJECT)
+    if (mtmp && M_AP_TYPE(mtmp) != M_AP_FURNITURE) {
+        if (M_AP_TYPE(mtmp) == M_AP_OBJECT)
             goto objhere;
         if (!quietly) {
             if ((mtmp->mx != x) || (mtmp->my != y)) {
diff --git a/src/mhitm.c b/src/mhitm.c
index 3a95815f7..a2d0c6659 100644
--- a/src/mhitm.c
+++ b/src/mhitm.c
@@ -94,9 +94,9 @@ struct attack *mattk;
             map_invisible(magr->mx, magr->my);
         if (!canspotmon(mdef))
             map_invisible(mdef->mx, mdef->my);
-        if (mdef->m_ap_type)
+        if (M_AP_TYPE(mdef))
             seemimic(mdef);
-        if (magr->m_ap_type)
+        if (M_AP_TYPE(magr))
             seemimic(magr);
         fmt = (could_seduce(magr, mdef, mattk) && !magr->mcan)
                   ? "%s pretends to be friendly to"
@@ -225,7 +225,7 @@ boolean quietly;
     /* undetected monster becomes un-hidden if it is displaced */
     if (mdef->mundetected)
         mdef->mundetected = 0;
-    if (mdef->m_ap_type && mdef->m_ap_type != M_AP_MONSTER)
+    if (M_AP_TYPE(mdef) && M_AP_TYPE(mdef) != M_AP_MONSTER)
         seemimic(mdef);
     /* wake up the displaced defender */
     mdef->msleeping = 0;
@@ -543,9 +543,9 @@ struct attack *mattk;
             map_invisible(magr->mx, magr->my);
         if (!canspotmon(mdef))
             map_invisible(mdef->mx, mdef->my);
-        if (mdef->m_ap_type)
+        if (M_AP_TYPE(mdef))
             seemimic(mdef);
-        if (magr->m_ap_type)
+        if (M_AP_TYPE(magr))
             seemimic(magr);
         if ((compat = could_seduce(magr, mdef, mattk)) && !magr->mcan) {
             Sprintf(buf, "%s %s", Monnam(magr),
@@ -599,7 +599,7 @@ struct attack *mattk;
 
     if (vis) {
         if (mdef->data->mlet == S_MIMIC
-            && mdef->m_ap_type != M_AP_NOTHING)
+            && M_AP_TYPE(mdef) != M_AP_NOTHING)
             seemimic(mdef);
         Sprintf(buf, "%s gazes at", Monnam(magr));
         pline("%s %s...", buf,
diff --git a/src/mhitu.c b/src/mhitu.c
index 25f10b660..fb44227c1 100644
--- a/src/mhitu.c
+++ b/src/mhitu.c
@@ -525,7 +525,7 @@ register struct monst *mtmp;
     }
 
     /* hero might be a mimic, concealed via #monster */
-    if (youmonst.data->mlet == S_MIMIC && youmonst.m_ap_type && !range2
+    if (youmonst.data->mlet == S_MIMIC && U_AP_TYPE && !range2
         && foundyou && !u.uswallow) {
         boolean sticky = sticks(youmonst.data);
 
@@ -545,7 +545,7 @@ register struct monst *mtmp;
     }
 
     /* non-mimic hero might be mimicking an object after eating m corpse */
-    if (youmonst.m_ap_type == M_AP_OBJECT && !range2 && foundyou
+    if (U_AP_TYPE == M_AP_OBJECT && !range2 && foundyou
         && !u.uswallow) {
         if (!canspotmon(mtmp))
             map_invisible(mtmp->mx, mtmp->my);
diff --git a/src/mon.c b/src/mon.c
index 11113b7e8..7dc5f7c48 100644
--- a/src/mon.c
+++ b/src/mon.c
@@ -799,8 +799,8 @@ movemon()
             /* unwatched mimics and piercers may hide again  [MRS] */
             if (restrap(mtmp))
                 continue;
-            if (mtmp->m_ap_type == M_AP_FURNITURE
-                || mtmp->m_ap_type == M_AP_OBJECT)
+            if (M_AP_TYPE(mtmp) == M_AP_FURNITURE
+                || M_AP_TYPE(mtmp) == M_AP_OBJECT)
                 continue;
             if (mtmp->mundetected)
                 continue;
@@ -1682,7 +1682,7 @@ struct monst **monst_list; /* &migrating_mons or &mydogs or null */
            clone can continue imitating some other monster form); also,
            might be imitating a boulder so need line-of-sight unblocking */
         mon->mundetected = 0;
-        if (mon->m_ap_type && mon->m_ap_type != M_AP_MONSTER)
+        if (M_AP_TYPE(mon) && M_AP_TYPE(mon) != M_AP_MONSTER)
             seemimic(mon);
     }
 
@@ -1821,7 +1821,7 @@ struct permonst *mptr; /* reflects mtmp->data _prior_ to mtmp's death */
     }
     if (emits_light(mptr))
         del_light_source(LS_MONSTER, monst_to_any(mtmp));
-    if (mtmp->m_ap_type)
+    if (M_AP_TYPE(mtmp))
         seemimic(mtmp);
     if (onmap)
         newsym(mtmp->mx, mtmp->my);
@@ -2870,7 +2870,7 @@ register struct monst *mtmp;
 boolean via_attack;
 {
     mtmp->msleeping = 0;
-    if (mtmp->m_ap_type) {
+    if (M_AP_TYPE(mtmp)) {
         seemimic(mtmp);
     } else if (context.forcefight && !context.mon_moving
                && mtmp->mundetected) {
@@ -2958,7 +2958,7 @@ rescham()
         }
         if (is_were(mtmp->data) && mtmp->data->mlet != S_HUMAN)
             new_were(mtmp);
-        if (mtmp->m_ap_type && cansee(mtmp->mx, mtmp->my)) {
+        if (M_AP_TYPE(mtmp) && cansee(mtmp->mx, mtmp->my)) {
             seemimic(mtmp);
             /* we pretend that the mimic doesn't
                know that it has been unmasked */
@@ -3015,7 +3015,7 @@ register struct monst *mtmp;
 {
     struct trap *t;
 
-    if (mtmp->mcan || mtmp->m_ap_type || cansee(mtmp->mx, mtmp->my)
+    if (mtmp->mcan || M_AP_TYPE(mtmp) || cansee(mtmp->mx, mtmp->my)
         || rn2(3) || mtmp == u.ustuck
         /* can't hide while trapped except in pits */
         || (mtmp->mtrapped && (t = t_at(mtmp->mx, mtmp->my)) != 0
@@ -3076,7 +3076,7 @@ struct monst *mon;
     boolean hider_under = hides_under(mon->data) || mon->data->mlet == S_EEL;
 
     if ((is_hider(mon->data) || hider_under)
-        && !(mon->mundetected || mon->m_ap_type)) {
+        && !(mon->mundetected || M_AP_TYPE(mon))) {
         xchar x = mon->mx, y = mon->my;
         char save_viz = viz_array[y][x];
 
@@ -3085,7 +3085,7 @@ struct monst *mon;
         if (is_hider(mon->data))
             (void) restrap(mon);
         /* try again if mimic missed its 1/3 chance to hide */
-        if (mon->data->mlet == S_MIMIC && !mon->m_ap_type)
+        if (mon->data->mlet == S_MIMIC && !M_AP_TYPE(mon))
             (void) restrap(mon);
         if (hider_under)
             (void) hideunder(mon);
@@ -3551,7 +3551,7 @@ boolean msg;      /* "The oldmon turns into a newmon!" */
         wormgone(mtmp);
         place_monster(mtmp, mtmp->mx, mtmp->my);
     }
-    if (mtmp->m_ap_type && mdat->mlet != S_MIMIC)
+    if (M_AP_TYPE(mtmp) && mdat->mlet != S_MIMIC)
         seemimic(mtmp); /* revert to normal monster */
 
     /* (this code used to try to adjust the monster's health based on
@@ -3940,7 +3940,7 @@ short otyp;
 {
     short ap = mtmp->mappearance;
 
-    switch (mtmp->m_ap_type) {
+    switch (M_AP_TYPE(mtmp)) {
     case M_AP_NOTHING:
     case M_AP_FURNITURE:
     case M_AP_MONSTER:
diff --git a/src/monmove.c b/src/monmove.c
index 305ba4cbb..942124c28 100644
--- a/src/monmove.c
+++ b/src/monmove.c
@@ -231,8 +231,8 @@ register struct monst *mtmp;
               || mtmp->data->mlet == S_LEPRECHAUN) || !rn2(50))
         && (Aggravate_monster
             || (mtmp->data->mlet == S_DOG || mtmp->data->mlet == S_HUMAN)
-            || (!rn2(7) && mtmp->m_ap_type != M_AP_FURNITURE
-                && mtmp->m_ap_type != M_AP_OBJECT))) {
+            || (!rn2(7) && M_AP_TYPE(mtmp) != M_AP_FURNITURE
+                && M_AP_TYPE(mtmp) != M_AP_OBJECT))) {
         mtmp->msleeping = 0;
         return 1;
     }
@@ -289,8 +289,8 @@ boolean fleemsg;
             mtmp->mfleetim = (unsigned) min(fleetime, 127);
         }
         if (!mtmp->mflee && fleemsg && canseemon(mtmp)
-            && mtmp->m_ap_type != M_AP_FURNITURE
-            && mtmp->m_ap_type != M_AP_OBJECT) {
+            && M_AP_TYPE(mtmp) != M_AP_FURNITURE
+            && M_AP_TYPE(mtmp) != M_AP_OBJECT) {
             /* unfortunately we can't distinguish between temporary
                sleep and temporary paralysis, so both conditions
                receive the same alternate message */
diff --git a/src/mthrowu.c b/src/mthrowu.c
index 862c6cca1..d10d2f1f1 100644
--- a/src/mthrowu.c
+++ b/src/mthrowu.c
@@ -313,7 +313,7 @@ boolean verbose;    /* give message(s) even when you can't see what happened */
     struct obj *mon_launcher = archer ? MON_WEP(archer) : NULL;
 
     notonhead = (bhitpos.x != mtmp->mx || bhitpos.y != mtmp->my);
-    ismimic = mtmp->m_ap_type && mtmp->m_ap_type != M_AP_MONSTER;
+    ismimic = M_AP_TYPE(mtmp) && M_AP_TYPE(mtmp) != M_AP_MONSTER;
     vis = cansee(bhitpos.x, bhitpos.y);
 
     tmp = 5 + find_mac(mtmp) + omon_adj(mtmp, otmp, FALSE);
@@ -1073,8 +1073,8 @@ register struct monst *mtmp;
 
     /* hero concealment usually trumps monst awareness of being lined up */
     if (Upolyd && rn2(25)
-        && (u.uundetected || (youmonst.m_ap_type != M_AP_NOTHING
-                              && youmonst.m_ap_type != M_AP_MONSTER)))
+        && (u.uundetected || (U_AP_TYPE != M_AP_NOTHING
+                              && U_AP_TYPE != M_AP_MONSTER)))
         return FALSE;
 
     ignore_boulders = (throws_rocks(mtmp->data)
diff --git a/src/objnam.c b/src/objnam.c
index af2365f55..06efd9bda 100644
--- a/src/objnam.c
+++ b/src/objnam.c
@@ -4111,7 +4111,7 @@ const char *
 mimic_obj_name(mtmp)
 struct monst *mtmp;
 {
-    if (mtmp->m_ap_type == M_AP_OBJECT) {
+    if (M_AP_TYPE(mtmp) == M_AP_OBJECT) {
         if (mtmp->mappearance == GOLD_PIECE)
             return "gold";
         if (mtmp->mappearance != STRANGE_OBJECT)
diff --git a/src/pager.c b/src/pager.c
index 8833a21bb..5ca886df6 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -89,7 +89,7 @@ char *outbuf;
             mons[u.umonnum].mname, plname);
     if (u.usteed)
         Sprintf(eos(outbuf), ", mounted on %s", y_monnam(u.usteed));
-    if (u.uundetected || (Upolyd && youmonst.m_ap_type))
+    if (u.uundetected || (Upolyd && U_AP_TYPE))
         mhidden_description(&youmonst, FALSE, eos(outbuf));
     return outbuf;
 }
@@ -109,12 +109,12 @@ char *outbuf;
                                                     : glyph_at(x, y);
 
     *outbuf = '\0';
-    if (mon->m_ap_type == M_AP_FURNITURE
-        || mon->m_ap_type == M_AP_OBJECT) {
+    if (M_AP_TYPE(mon) == M_AP_FURNITURE
+        || M_AP_TYPE(mon) == M_AP_OBJECT) {
         Strcpy(outbuf, ", mimicking ");
-        if (mon->m_ap_type == M_AP_FURNITURE) {
+        if (M_AP_TYPE(mon) == M_AP_FURNITURE) {
             Strcat(outbuf, an(defsyms[mon->mappearance].explanation));
-        } else if (mon->m_ap_type == M_AP_OBJECT
+        } else if (M_AP_TYPE(mon) == M_AP_OBJECT
                    /* remembered glyph, not glyph_at() which is 'mon' */
                    && glyph_is_object(glyph)) {
  objfrommap:
@@ -130,7 +130,7 @@ char *outbuf;
         } else {
             Strcat(outbuf, something);
         }
-    } else if (mon->m_ap_type == M_AP_MONSTER) {
+    } else if (M_AP_TYPE(mon) == M_AP_MONSTER) {
         if (altmon)
             Sprintf(outbuf, ", masquerading as %s",
                     an(mons[mon->mappearance].mname));
@@ -160,7 +160,7 @@ object_from_map(glyph, x, y, obj_p)
 int glyph, x, y;
 struct obj **obj_p;
 {
-    boolean fakeobj = FALSE;
+    boolean fakeobj = FALSE, mimic_obj = FALSE;
     struct monst *mtmp;
     struct obj *otmp;
     int glyphotyp = glyph_to_obj(glyph);
@@ -174,9 +174,10 @@ struct obj **obj_p;
 
     /* there might be a mimic here posing as an object */
     mtmp = m_at(x, y);
-    if (mtmp && is_obj_mappear(mtmp, (unsigned) glyphotyp))
+    if (mtmp && is_obj_mappear(mtmp, (unsigned) glyphotyp)) {
         otmp = 0;
-    else
+        mimic_obj = TRUE;
+    } else
         mtmp = 0;
 
     if (!otmp || otmp->otyp != glyphotyp) {
@@ -214,7 +215,11 @@ struct obj **obj_p;
         /* terrain mode views what's already known, doesn't learn new stuff */
         && !iflags.terrainmode) /* so don't set dknown when in terrain mode */
         otmp->dknown = 1; /* if a pile, clearly see the top item only */
-
+    if (fakeobj && mtmp && mimic_obj &&
+        (otmp->dknown || (M_AP_FLAG(mtmp) & M_AP_F_DKNOWN))) {
+            mtmp->m_ap_type |= M_AP_F_DKNOWN;
+            otmp->dknown = 1;
+    }
     *obj_p = otmp;
     return fakeobj; /* when True, caller needs to dealloc *obj_p */
 }
@@ -299,7 +304,7 @@ int x, y;
 
     /* we know the hero sees a monster at this location, but if it's shown
        due to persistant monster detection he might remember something else */
-    if (mtmp->mundetected || mtmp->m_ap_type)
+    if (mtmp->mundetected || M_AP_TYPE(mtmp))
         mhidden_description(mtmp, FALSE, eos(buf));
 
     if (monbuf) {
diff --git a/src/polyself.c b/src/polyself.c
index c30ac6583..8ed827906 100644
--- a/src/polyself.c
+++ b/src/polyself.c
@@ -162,7 +162,7 @@ polyman(fmt, arg)
 const char *fmt, *arg;
 {
     boolean sticky = (sticks(youmonst.data) && u.ustuck && !u.uswallow),
-            was_mimicking = (youmonst.m_ap_type == M_AP_OBJECT);
+            was_mimicking = (U_AP_TYPE == M_AP_OBJECT);
     boolean was_blind = !!Blind;
 
     if (Upolyd) {
@@ -625,7 +625,7 @@ int mntmp;
     }
 
     /* if stuck mimicking gold, stop immediately */
-    if (multi < 0 && youmonst.m_ap_type == M_AP_OBJECT
+    if (multi < 0 && U_AP_TYPE == M_AP_OBJECT
         && youmonst.data->mlet != S_MIMIC)
         unmul("");
     /* if becoming a non-mimic, stop mimicking anything */
@@ -1323,8 +1323,8 @@ dogaze()
                 pline("%s seems not to notice your gaze.", Monnam(mtmp));
             } else if (mtmp->minvis && !See_invisible) {
                 You_cant("see where to gaze at %s.", Monnam(mtmp));
-            } else if (mtmp->m_ap_type == M_AP_FURNITURE
-                       || mtmp->m_ap_type == M_AP_OBJECT) {
+            } else if (M_AP_TYPE(mtmp) == M_AP_FURNITURE
+                       || M_AP_TYPE(mtmp) == M_AP_OBJECT) {
                 looked--;
                 continue;
             } else if (flags.safe_dog && mtmp->mtame && !Confusion) {
@@ -1432,7 +1432,7 @@ dohide()
                        : (humanoid(u.ustuck->data) ? "holding someone"
                                                    : "holding that creature"));
         if (u.uundetected
-            || (ismimic && youmonst.m_ap_type != M_AP_NOTHING)) {
+            || (ismimic && U_AP_TYPE != M_AP_NOTHING)) {
             u.uundetected = 0;
             youmonst.m_ap_type = M_AP_NOTHING;
             newsym(u.ux, u.uy);
@@ -1470,7 +1470,7 @@ dohide()
      * else make youhiding() give smarter messages at such spots.
      */
 
-    if (u.uundetected || (ismimic && youmonst.m_ap_type != M_AP_NOTHING)) {
+    if (u.uundetected || (ismimic && U_AP_TYPE != M_AP_NOTHING)) {
         youhiding(FALSE, 1); /* "you are already hiding" */
         return 0;
     }
diff --git a/src/shk.c b/src/shk.c
index 1817d9bec..d5ad782bd 100644
--- a/src/shk.c
+++ b/src/shk.c
@@ -517,8 +517,8 @@ deserted_shop(enterstring)
                 continue;
             if ((mtmp = m_at(x, y)) != 0) {
                 ++n;
-                if (sensemon(mtmp) || ((mtmp->m_ap_type == M_AP_NOTHING
-                                        || mtmp->m_ap_type == M_AP_MONSTER)
+                if (sensemon(mtmp) || ((M_AP_TYPE(mtmp) == M_AP_NOTHING
+                                        || M_AP_TYPE(mtmp) == M_AP_MONSTER)
                                        && canseemon(mtmp)))
                     ++m;
             }
diff --git a/src/sounds.c b/src/sounds.c
index 7d4c0be63..505a10e56 100644
--- a/src/sounds.c
+++ b/src/sounds.c
@@ -1059,8 +1059,8 @@ dochat()
         return 0;
     }
 
-    if (!mtmp || mtmp->mundetected || mtmp->m_ap_type == M_AP_FURNITURE
-        || mtmp->m_ap_type == M_AP_OBJECT)
+    if (!mtmp || mtmp->mundetected || M_AP_TYPE(mtmp) == M_AP_FURNITURE
+        || M_AP_TYPE(mtmp) == M_AP_OBJECT)
         return 0;
 
     /* sleeping monsters won't talk, except priests (who wake up) */
diff --git a/src/steed.c b/src/steed.c
index feede89c5..f7ad61024 100644
--- a/src/steed.c
+++ b/src/steed.c
@@ -238,8 +238,8 @@ boolean force;      /* Quietly force this animal */
 
     /* Can the player reach and see the monster? */
     if (!mtmp || (!force && ((Blind && !Blind_telepat) || mtmp->mundetected
-                             || mtmp->m_ap_type == M_AP_FURNITURE
-                             || mtmp->m_ap_type == M_AP_OBJECT))) {
+                             || M_AP_TYPE(mtmp) == M_AP_FURNITURE
+                             || M_AP_TYPE(mtmp) == M_AP_OBJECT))) {
         pline("I see nobody there.");
         return (FALSE);
     }
diff --git a/src/trap.c b/src/trap.c
index f422241a6..02d1030ef 100644
--- a/src/trap.c
+++ b/src/trap.c
@@ -632,7 +632,7 @@ int *fail_reason;
     if (has_oname(statue) && !unique_corpstat(mon->data))
         mon = christen_monst(mon, ONAME(statue));
     /* mimic statue becomes seen mimic; other hiders won't be hidden */
-    if (mon->m_ap_type)
+    if (M_AP_TYPE(mon))
         seemimic(mon);
     else
         mon->mundetected = FALSE;
@@ -4444,8 +4444,8 @@ boolean force;
                     return 1;
                 }
                 if ((mtmp = m_at(x, y)) != 0
-                    && (mtmp->m_ap_type == M_AP_FURNITURE
-                        || mtmp->m_ap_type == M_AP_OBJECT)) {
+                    && (M_AP_TYPE(mtmp) == M_AP_FURNITURE
+                        || M_AP_TYPE(mtmp) == M_AP_OBJECT)) {
                     stumble_onto_mimic(mtmp);
                     return 1;
                 }
diff --git a/src/uhitm.c b/src/uhitm.c
index a02bc80f4..b354d5d7a 100644
--- a/src/uhitm.c
+++ b/src/uhitm.c
@@ -146,7 +146,7 @@ struct obj *wep; /* uwep for attack(), null for kick_monster() */
         /* if it was an invisible mimic, treat it as if we stumbled
          * onto a visible mimic
          */
-        if (mtmp->m_ap_type && !Protection_from_shape_changers
+        if (M_AP_TYPE(mtmp) && !Protection_from_shape_changers
             /* applied pole-arm attack is too far to get stuck */
             && distu(mtmp->mx, mtmp->my) <= 2) {
             if (!u.ustuck && !mtmp->mflee && dmgtype(mtmp->data, AD_STCK))
@@ -162,7 +162,7 @@ struct obj *wep; /* uwep for attack(), null for kick_monster() */
         return TRUE;
     }
 
-    if (mtmp->m_ap_type && !Protection_from_shape_changers && !sensemon(mtmp)
+    if (M_AP_TYPE(mtmp) && !Protection_from_shape_changers && !sensemon(mtmp)
         && !glyph_is_warning(glyph)) {
         /* If a hidden mimic was in a square where a player remembers
          * some (probably different) unseen monster, the player is in
@@ -204,7 +204,7 @@ struct obj *wep; /* uwep for attack(), null for kick_monster() */
      * make sure to wake up a monster from the above cases if the
      * hero can sense that the monster is there.
      */
-    if ((mtmp->mundetected || mtmp->m_ap_type) && sensemon(mtmp)) {
+    if ((mtmp->mundetected || M_AP_TYPE(mtmp)) && sensemon(mtmp)) {
         mtmp->mundetected = 0;
         wakeup(mtmp, TRUE);
     }
@@ -2993,7 +2993,7 @@ struct monst *mtmp;
     if (Blind) {
         if (!Blind_telepat)
             what = generic; /* with default fmt */
-        else if (mtmp->m_ap_type == M_AP_MONSTER)
+        else if (M_AP_TYPE(mtmp) == M_AP_MONSTER)
             what = a_monnam(mtmp); /* differs from what was sensed */
     } else {
         int glyph = levl[u.ux + u.dx][u.uy + u.dy].glyph;
diff --git a/src/vault.c b/src/vault.c
index 0e86803da..7340ba2a4 100644
--- a/src/vault.c
+++ b/src/vault.c
@@ -412,8 +412,8 @@ invault()
             mongone(guard);
             return;
         }
-        if (youmonst.m_ap_type == M_AP_OBJECT || u.uundetected) {
-            if (youmonst.m_ap_type == M_AP_OBJECT
+        if (U_AP_TYPE == M_AP_OBJECT || u.uundetected) {
+            if (U_AP_TYPE == M_AP_OBJECT
                 && youmonst.mappearance != GOLD_PIECE)
                 if (!Deaf)
                     verbalize("Hey!  Who left that %s in here?",
diff --git a/src/zap.c b/src/zap.c
index 755f83c76..a9350eb4f 100644
--- a/src/zap.c
+++ b/src/zap.c
@@ -144,7 +144,7 @@ struct obj *otmp;
     const char *zap_type_text = "spell";
     struct obj *obj;
     boolean disguised_mimic = (mtmp->data->mlet == S_MIMIC
-                               && mtmp->m_ap_type != M_AP_NOTHING);
+                               && M_AP_TYPE(mtmp) != M_AP_NOTHING);
 
     if (u.uswallow && mtmp == u.ustuck)
         reveal_invis = FALSE;
@@ -461,7 +461,7 @@ struct obj *otmp;
             m_respond(mtmp);
             if (mtmp->isshk && !*u.ushops)
                 hot_pursuit(mtmp);
-        } else if (mtmp->m_ap_type)
+        } else if (M_AP_TYPE(mtmp))
             seemimic(mtmp); /* might unblock if mimicing a boulder/door */
     }
     /* note: bhitpos won't be set if swallowed, but that's okay since
@@ -826,7 +826,7 @@ boolean by_hero;
         mtmp->mundetected = 0;
         newsym(mtmp->mx, mtmp->my);
     }
-    if (mtmp->m_ap_type)
+    if (M_AP_TYPE(mtmp))
         seemimic(mtmp);
 
     one_of = (corpse->quan > 1L);
@@ -2755,7 +2755,7 @@ boolean youattack, allow_cancel_kill, self_cancel;
     } else {
         mdef->mcan = 1;
         /* force shapeshifter into its base form */
-        if (mdef->m_ap_type != M_AP_NOTHING)
+        if (M_AP_TYPE(mdef) != M_AP_NOTHING)
             seemimic(mdef);
         /* [not 'else if'; chameleon might have been hiding as a mimic] */
         if (mdef->cham >= LOW_PM) {