diff --git a/include/extern.h b/include/extern.h
index 6fd1df12f..6f355fa07 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -1,4 +1,4 @@
-/* NetHack 3.6	extern.h	$NHDT-Date: 1513130012 2017/12/13 01:53:32 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.621 $ */
+/* NetHack 3.6	extern.h	$NHDT-Date: 1514769568 2018/01/01 01:19:28 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.622 $ */
 /* Copyright (c) Steve Creps, 1988.				  */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -1397,6 +1397,7 @@ E void FDECL(restore_cham, (struct monst *));
 E boolean FDECL(hideunder, (struct monst *));
 E void FDECL(hide_monst, (struct monst *));
 E void FDECL(mon_animal_list, (BOOLEAN_P));
+E boolean FDECL(validvamp, (struct monst *, int *, int));
 E int FDECL(select_newcham_form, (struct monst *));
 E void FDECL(mgender_from_permonst, (struct monst *, struct permonst *));
 E int FDECL(newcham,
diff --git a/src/mon.c b/src/mon.c
index a872b93a9..62fb34a8f 100644
--- a/src/mon.c
+++ b/src/mon.c
@@ -1,4 +1,4 @@
-/* NetHack 3.6	mon.c	$NHDT-Date: 1505266804 2017/09/13 01:40:04 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.244 $ */
+/* NetHack 3.6	mon.c	$NHDT-Date: 1514769571 2018/01/01 01:19:31 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.246 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -23,7 +23,6 @@ STATIC_DCL void FDECL(kill_eggs, (struct obj *));
 STATIC_DCL int FDECL(pickvampshape, (struct monst *));
 STATIC_DCL boolean FDECL(isspecmon, (struct monst *));
 STATIC_DCL boolean FDECL(validspecmon, (struct monst *, int));
-STATIC_DCL boolean FDECL(validvamp, (struct monst *, int *, int));
 STATIC_DCL struct permonst *FDECL(accept_newcham_form, (int));
 STATIC_DCL struct obj *FDECL(make_corpse, (struct monst *, unsigned));
 STATIC_DCL void FDECL(m_detach, (struct monst *, struct permonst *));
@@ -3162,7 +3161,7 @@ int mndx;
 }
 
 /* prevent wizard mode user from specifying invalid vampshifter shape */
-STATIC_OVL boolean
+boolean
 validvamp(mon, mndx_p, monclass)
 struct monst *mon;
 int *mndx_p, monclass;
diff --git a/src/sp_lev.c b/src/sp_lev.c
index 170a6e251..e2d362c6c 100644
--- a/src/sp_lev.c
+++ b/src/sp_lev.c
@@ -1,4 +1,4 @@
-/* NetHack 3.6	sp_lev.c	$NHDT-Date: 1514720301 2017/12/31 11:38:21 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.94 $ */
+/* NetHack 3.6	sp_lev.c	$NHDT-Date: 1514769572 2018/01/01 01:19:32 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.95 $ */
 /*      Copyright (c) 1989 by Jean-Christophe Collet */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -1589,11 +1589,14 @@ struct mkroom *croom;
             mtmp = christen_monst(mtmp, m->name.str);
 
         /*
-         * This is currently hardwired for mimics only.  It should
-         * eventually be expanded.
+         * This doesn't complain if an attempt is made to give a
+         * non-mimic/non-shapechanger an appearance or to give a
+         * shapechanger a non-monster shape, it just refuses to comply.
          */
         if (m->appear_as.str
-            && ((mtmp->data->mlet == S_MIMIC) || mtmp->cham >= LOW_PM)
+            && ((mtmp->data->mlet == S_MIMIC)
+                /* shapechanger (chameleons, et al, and vampires) */
+                || (mtmp->cham >= LOW_PM && m->appear == M_AP_MONSTER))
             && !Protection_from_shape_changers) {
             int i;
 
@@ -1658,7 +1661,29 @@ struct mkroom *croom;
                     mndx = select_newcham_form(mtmp);
                 else
                     mndx = name_to_mon(m->appear_as.str);
-                if ((mndx != NON_PM) && (&mons[mndx] != mtmp->data)) {
+
+                if (mndx == NON_PM || (is_vampshifter(mtmp)
+                                       && !validvamp(mtmp, &mndx, S_HUMAN))) {
+                    impossible("create_monster: invalid %s (\"%s\")",
+                               (mtmp->data->mlet == S_MIMIC)
+                                 ? "mimic appearance"
+                                 : (mtmp->data == &mons[PM_WIZARD_OF_YENDOR])
+                                     ? "Wizard appearance"
+                                     : is_vampshifter(mtmp)
+                                         ? "vampire shape"
+                                         : "chameleon shape",
+                               m->appear_as.str);
+                } else if (&mons[mndx] == mtmp->data) {
+                    /* explicitly forcing a mimic to appear as itself */
+                    mtmp->m_ap_type = M_AP_NOTHING;
+                    mtmp->mappearance = 0;
+                } else if (mtmp->data->mlet == S_MIMIC
+                           || mtmp->data == &mons[PM_WIZARD_OF_YENDOR]) {
+                    /* this is ordinarily only used for Wizard clones
+                       and hasn't been exhaustively tested for mimics */
+                    mtmp->m_ap_type = M_AP_MONSTER;
+                    mtmp->mappearance = mndx;
+                } else { /* chameleon or vampire */
                     struct permonst *mdat = &mons[mndx];
                     struct permonst *olddata = mtmp->data;