diff --git a/include/extern.h b/include/extern.h
index 502035219..ee0a4dc75 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -1559,6 +1559,7 @@ extern void mon_to_stone(struct monst *);
 extern void m_into_limbo(struct monst *);
 extern void migrate_mon(struct monst *, coordxy, coordxy);
 extern void mnexto(struct monst *, unsigned);
+extern void deal_with_overcrowding(struct monst *);
 extern void maybe_mnexto(struct monst *);
 extern int mnearto(struct monst *, coordxy, coordxy, boolean, unsigned);
 extern void m_respond(struct monst *);
@@ -1571,7 +1572,9 @@ extern void seemimic(struct monst *);
 extern void normal_shape(struct monst *);
 extern void iter_mons(void (*)(struct monst *));
 extern struct monst *get_iter_mons(boolean (*)(struct monst *));
-extern struct monst *get_iter_mons_xy(boolean (*)(struct monst *, coordxy, coordxy), coordxy, coordxy);
+extern struct monst *get_iter_mons_xy(boolean (*)(struct monst *,
+                                                  coordxy, coordxy),
+                                      coordxy, coordxy);
 extern void rescham(void);
 extern void restartcham(void);
 extern void restore_cham(struct monst *);
diff --git a/src/mhitm.c b/src/mhitm.c
index 7bdd48495..a51dc9db5 100644
--- a/src/mhitm.c
+++ b/src/mhitm.c
@@ -719,7 +719,8 @@ engulf_target(struct monst *magr, struct monst *mdef)
     int dx, dy;
 
     /* can't swallow something that's too big */
-    if (mdef->data->msize >= MZ_HUGE)
+    if (mdef->data->msize >= MZ_HUGE
+        || (magr->data->msize < mdef->data->msize && !is_whirly(magr->data)))
         return FALSE;
 
     /* can't (move to) swallow if trapped. TODO: could do some? */
diff --git a/src/mhitu.c b/src/mhitu.c
index 3e9a13b7a..d7f3ced28 100644
--- a/src/mhitu.c
+++ b/src/mhitu.c
@@ -1151,16 +1151,17 @@ gulpmu(struct monst *mtmp, struct attack *mattk)
         place_monster(mtmp, u.ux, u.uy);
         set_ustuck(mtmp);
         newsym(mtmp->mx, mtmp->my);
-        if (is_animal(mtmp->data) && u.usteed) {
+        /* 3.7: dismount for all engulfers, not just for purple worms */
+        if (u.usteed) {
             char buf[BUFSZ];
 
-            /* Too many quirks presently if hero and steed
-             * are swallowed. Pretend purple worms don't
-             * like horses for now :-)
-             */
             Strcpy(buf, mon_nam(u.usteed));
-            urgent_pline("%s lunges forward and plucks you off %s!",
-                         Monnam(mtmp), buf);
+            urgent_pline("%s %s forward and plucks you off %s!",
+                         Some_Monnam(mtmp),
+                         is_animal(mtmp->data) ? "lunges"
+                           : amorphous(mtmp->data) ? "oozes"
+                             : "surges",
+                         buf);
             dismount_steed(DISMOUNT_ENGULFED);
         } else {
             urgent_pline("%s engulfs you!", Monnam(mtmp));
@@ -1184,7 +1185,11 @@ gulpmu(struct monst *mtmp, struct attack *mattk)
 
         if (touch_petrifies(g.youmonst.data) && !resists_ston(mtmp)) {
             /* put the attacker back where it started;
-               the resulting statue will end up there */
+               the resulting statue will end up there
+               [note: if poly'd hero could ride or non-poly'd hero could
+               acquire touch_petrifies() capability somehow, this code
+               would need to deal with possibility of steed having taken
+               engulfer's previous spot when hero was forcibly dismounted] */
             remove_monster(mtmp->mx, mtmp->my); /* u.ux,u.uy */
             place_monster(mtmp, omx, omy);
             minstapetrify(mtmp, TRUE);
diff --git a/src/mon.c b/src/mon.c
index 2e253a7d5..dd4c9a0af 100644
--- a/src/mon.c
+++ b/src/mon.c
@@ -20,7 +20,6 @@ static void m_detach(struct monst *, struct permonst *);
 static void set_mon_min_mhpmax(struct monst *, int);
 static void lifesaved_monster(struct monst *);
 static boolean ok_to_obliterate(struct monst *);
-static void deal_with_overcrowding(struct monst *);
 static void m_restartcham(struct monst *);
 static boolean restrap(struct monst *);
 static int pick_animal(void);
@@ -3444,7 +3443,7 @@ elemental_clog(struct monst *mon)
 /* make monster mtmp next to you (if possible);
    might place monst on far side of a wall or boulder */
 void
-mnexto(struct monst* mtmp, unsigned int rlocflags)
+mnexto(struct monst *mtmp, unsigned int rlocflags)
 {
     coord mm;
 
@@ -3463,8 +3462,8 @@ mnexto(struct monst* mtmp, unsigned int rlocflags)
     return;
 }
 
-static void
-deal_with_overcrowding(struct monst* mtmp)
+void
+deal_with_overcrowding(struct monst *mtmp)
 {
     if (In_endgame(&u.uz)) {
         debugpline1("overcrowding: elemental_clog on %s", m_monnam(mtmp));
@@ -3477,7 +3476,7 @@ deal_with_overcrowding(struct monst* mtmp)
 
 /* like mnexto() but requires destination to be directly accessible */
 void
-maybe_mnexto(struct monst* mtmp)
+maybe_mnexto(struct monst *mtmp)
 {
     coord mm;
     struct permonst *ptr = mtmp->data;
diff --git a/src/monmove.c b/src/monmove.c
index 2a280f806..9608fdb52 100644
--- a/src/monmove.c
+++ b/src/monmove.c
@@ -218,9 +218,10 @@ onscary(coordxy x, coordxy y, struct monst* mtmp)
 
 /* regenerate lost hit points */
 void
-mon_regen(struct monst* mon, boolean digest_meal)
+mon_regen(struct monst *mon, boolean digest_meal)
 {
-    if (mon->mhp < mon->mhpmax && (g.moves % 20 == 0 || regenerates(mon->data)))
+    if (mon->mhp < mon->mhpmax
+        && (g.moves % 20 == 0 || regenerates(mon->data)))
         mon->mhp++;
     if (mon->mspec_used)
         mon->mspec_used--;
@@ -238,7 +239,7 @@ mon_regen(struct monst* mon, boolean digest_meal)
  * jolted awake.
  */
 static int
-disturb(register struct monst* mtmp)
+disturb(register struct monst *mtmp)
 {
     /*
      * + Ettins are hard to surprise.
@@ -273,7 +274,7 @@ disturb(register struct monst* mtmp)
 
 /* ungrab/expel held/swallowed hero */
 static void
-release_hero(struct monst* mon)
+release_hero(struct monst *mon)
 {
     if (mon == u.ustuck) {
         if (u.uswallow) {
@@ -416,7 +417,9 @@ monflee(
 }
 
 static void
-distfleeck(register struct monst* mtmp, int* inrange, int* nearby, int* scared)
+distfleeck(
+    struct monst *mtmp,
+    int *inrange, int *nearby, int *scared) /* output */
 {
     int seescaryx, seescaryy;
     boolean sawscary = FALSE, bravegremlin = (rn2(5) == 0);
@@ -1123,12 +1126,22 @@ m_move(register struct monst* mtmp, register int after)
 
     /* likewise for shopkeeper, guard, or priest */
     if (mtmp->isshk || mtmp->isgd || mtmp->ispriest) {
-        int xm = mtmp->isshk ? shk_move(mtmp) : (mtmp->isgd ? gd_move(mtmp) : pri_move(mtmp));
+        int xm = mtmp->isshk ? shk_move(mtmp)
+                 : mtmp->isgd ? gd_move(mtmp)
+                   : pri_move(mtmp);
+
         switch (xm) {
-        case -2: return MMOVE_DIED;
-        case -1: mmoved = MMOVE_NOTHING; break; /* shk follow hero outside shop */
-        case 0: mmoved = MMOVE_NOTHING; goto postmov;
-        case 1: mmoved = MMOVE_MOVED; goto postmov;
+        case -2:
+            return MMOVE_DIED;
+        case -1:
+            mmoved = MMOVE_NOTHING; /* shk follow hero outside shop */
+            break;
+        case 0:
+            mmoved = MMOVE_NOTHING;
+            goto postmov;
+        case 1:
+            mmoved = MMOVE_MOVED;
+            goto postmov;
         default: impossible("unknown shk/gd/pri_move return value (%i)", xm);
             mmoved = MMOVE_NOTHING;
             goto postmov;
@@ -1343,10 +1356,10 @@ m_move(register struct monst* mtmp, register int after)
     niy = omy;
     flag = mon_allowflags(mtmp);
     {
-        register int i, j, nx, ny, nearer;
+        int i, j, nx, ny, nearer;
         int jcnt, cnt;
         int ndist, nidist;
-        register coord *mtrk;
+        coord *mtrk;
         coord poss[9];
 
         cnt = mfndpos(mtmp, poss, info, flag);
diff --git a/src/steed.c b/src/steed.c
index e9848c42e..515d35819 100644
--- a/src/steed.c
+++ b/src/steed.c
@@ -589,11 +589,13 @@ dismount_steed(
             (void) enexto(&steedcc, u.ux, u.uy, &mons[PM_GHOST]);
     }
     if (!m_at(steedcc.x, steedcc.y)) {
-        if (mtmp->mhp < 1)
-            mtmp->mhp = 0; /* make sure it isn't negative */
-        mtmp->mhp++; /* force at least one hit point, possibly resurrecting */
+        if (mtmp->mhp < 1) /* make sure it isn't negative so that */
+            mtmp->mhp = 0; /* ++mhp produces a positive value     */
+        mtmp->mhp++; /* force at least one hit point, possibly resurrecting
+                      * to avoid impossible("placing defunct monst on map") */
         place_monster(mtmp, steedcc.x, steedcc.y);
-        mtmp->mhp--; /* take the extra hit point away: cancel resurrection */
+        mtmp->mhp--; /* take the extra hit point away: cancel resurrection
+                      * if former steed has died */
     } else {
         impossible("Dismounting: can't place former steed on map.");
     }
@@ -610,7 +612,9 @@ dismount_steed(
             return;
         }
 
-        /* Set hero's and/or steed's positions.  Try moving the hero first. */
+        /* Set hero's and/or steed's positions.  Usually try moving the
+           hero first.  Note: for DISMOUNT_ENGULFED, caller hasn't set
+           u.uswallow yet but has set u.ustuck. */
         if (!u.uswallow && !u.ustuck && have_spot) {
             struct permonst *mdat = mtmp->data;
 
@@ -673,8 +677,9 @@ dismount_steed(
             rloc_to(mtmp, cc.x, cc.y);
             /* Player stays put */
 
-        /* Otherwise, kill the steed. */
+        /* Otherwise, steed goes bye-bye. */
         } else {
+#if 1       /* original there's-no-room handling */
             if (reason == DISMOUNT_BYCHOICE) {
                 /* [un]#ride: hero gets credit/blame for killing steed */
                 killed(mtmp);
@@ -684,6 +689,18 @@ dismount_steed(
                    damage type is just "neither AD_DGST nor -AD_RBRE" */
                 monkilled(mtmp, "", -AD_PHYS);
             }
+#else
+            /* Can't use this [yet?] because it violates monmove()'s
+             * assumption that a moving monster (engulfer) can't cause
+             * another monster (steed) to be removed from the fmon list.
+             * That other monster (steed) might be cached as the next one
+             * to move.
+             */
+            /* migrate back to this level if hero leaves and returns
+               or to next level if it is happening in the endgame */
+            mdrop_special_objs(mtmp);
+            deal_with_overcrowding(mtmp);
+#endif
         }
     } /* !DEADMONST(mtmp) */