another #1441 follow-up bit

src/uhitm.c

@@ -6267,6 +6267,13 @@ mimic_disguised_as_non_mon(struct monst *mtmp)
             && M_AP_TYPE(mtmp) != M_AP_MONSTER);
 }
 
+boolean
+mimic_disguised_as_mon(struct monst *mtmp)
+{
+    return (M_AP_TYPE(mtmp)
+            && M_AP_TYPE(mtmp) == M_AP_MONSTER);
+}
+
 staticfn void
 nohandglow(struct monst *mon)
 {

src/zap.c

@@ -192,7 +192,7 @@ bhitm(struct monst *mtmp, struct obj *otmp)
         reveal_invis = TRUE;
         learn_it = cansee(gb.bhitpos.x, gb.bhitpos.y);
         if (resists_magm(mtmp)) { /* match effect on player */
-            if (mimic_disguised_as_non_mon(mtmp))
+            if (!mimic_disguised_as_mon(mtmp))
                 seemimic(mtmp);
             shieldeff(mtmp->mx, mtmp->my);
             pline("Boing!");