diff --git a/include/extern.h b/include/extern.h
index 0f7c04a00..1b31ea989 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -1827,6 +1827,7 @@ extern void mon_track_add(struct monst *, coordxy, coordxy) NONNULLARG1;
 extern void mon_track_clear(struct monst *) NONNULLARG1;
 extern boolean monhaskey(struct monst *, boolean) NONNULLARG1;
 extern void mon_regen(struct monst *, boolean) NONNULLARG1;
+extern void m_postmove_effect(struct monst *) NONNULLARG1;
 extern int dochugw(struct monst *, boolean) NONNULLARG1;
 extern boolean onscary(coordxy, coordxy, struct monst *) NONNULLARG3;
 extern struct monst *find_pmmonst(int);
diff --git a/src/hack.c b/src/hack.c
index 3a449ab3d..59d126055 100644
--- a/src/hack.c
+++ b/src/hack.c
@@ -2692,6 +2692,9 @@ domove_core(void)
     /* tentatively move the hero plus steed; leave CLIPPING til later */
     u.ux += u.dx;
     u.uy += u.dy;
+
+    m_postmove_effect(&gy.youmonst);
+
     if (u.usteed) {
         u.usteed->mx = u.ux;
         u.usteed->my = u.uy;
diff --git a/src/monmove.c b/src/monmove.c
index b0a25e3ae..dfd39f2f7 100644
--- a/src/monmove.c
+++ b/src/monmove.c
@@ -593,6 +593,26 @@ mind_blast(struct monst *mtmp)
     }
 }
 
+/* do whatever effects monster has after moving.
+   called for both monsters and polyed hero.
+   for hero, called after location changes,
+   to prevent spam messages for hero getting enveloped in a cloud.
+   for monsters, called before location changes,
+   because monsters don't have "previous location" field */
+void
+m_postmove_effect(struct monst *mtmp)
+{
+    boolean is_u = (mtmp == &gy.youmonst) ? TRUE : FALSE;
+    coordxy x = is_u ? u.ux0 : mtmp->mx,
+        y = is_u ? u.uy0 : mtmp->my;
+
+    /* Hezrous create clouds of stench. This does not cost a move. */
+    if (mtmp->data == &mons[PM_HEZROU]) /* stench */
+        create_gas_cloud(x, y, 1, 8);
+    else if (mtmp->data == &mons[PM_STEAM_VORTEX] && !mtmp->mcan)
+        create_gas_cloud(x, y, 1, 0); /* harmless vapor */
+}
+
 /* returns 1 if monster died moving, 0 otherwise */
 /* The whole dochugw/m_move/distfleeck/mfndpos section is serious spaghetti
  * code. --KAA
@@ -780,12 +800,6 @@ dochug(struct monst *mtmp)
      * PHASE THREE: Now the actual movement phase
      */
 
-    /* Hezrous create clouds of stench. This does not cost a move. */
-    if (mtmp->data == &mons[PM_HEZROU]) /* stench */
-        create_gas_cloud(mtmp->mx, mtmp->my, 1, 8);
-    else if (mtmp->data == &mons[PM_STEAM_VORTEX] && !mtmp->mcan)
-        create_gas_cloud(mtmp->mx, mtmp->my, 1, 0); /* harmless vapor */
-
     /* A killer bee may eat honey in order to turn into a queen bee,
        costing it a move. */
     if (mdat == &mons[PM_KILLER_BEE]
@@ -1887,6 +1901,8 @@ m_move(struct monst *mtmp, int after)
             return MMOVE_DONE;
         }
 
+        m_postmove_effect(mtmp);
+
         /* move a normal monster; for a long worm, remove_monster() and
            place_monster() only manipulate the head; they leave tail as-is */
         remove_monster(omx, omy);