diff --git a/src/zap.c b/src/zap.c
index 7cceffba3..c43598386 100644
--- a/src/zap.c
+++ b/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_mon(mtmp))
+            if (disguised_mimic && !mimic_disguised_as_mon(mtmp))
                 seemimic(mtmp);
             shieldeff(mtmp->mx, mtmp->my);
             pline("Boing!");