diff --git a/src/do.c b/src/do.c
index 84a1f8b23..28d745082 100644
--- a/src/do.c
+++ b/src/do.c
@@ -159,7 +159,9 @@ const char *verb;
             if (mtmp) {
                 if (!passes_walls(mtmp->data) && !throws_rocks(mtmp->data)) {
                     int dieroll = rnd(20);
-                    if (hmon(mtmp, obj, TRUE, dieroll) && !is_whirly(mtmp->data))
+
+                    if (hmon(mtmp, obj, HMON_THROWN, dieroll)
+                        && !is_whirly(mtmp->data))
                         return FALSE; /* still alive */
                 }
                 mtmp->mtrapped = 0;