diff --git a/src/mapgen.cpp b/src/mapgen.cpp
index 743fa1f51f5b7..bc4b3f7bb4e25 100644
--- a/src/mapgen.cpp
+++ b/src/mapgen.cpp
@@ -13034,7 +13034,7 @@ void map::add_extra(map_extra type)
                 if (rng(1, 9) >= trig_dist(x, y, i, j)) {
                     marlossify(i, j);
                     if (one_in(15)) {
-                        monster creature(GetMType(monids[rng(0, 5)]));
+                        monster creature(GetMType(monids[rng(0, 4)]));
                         creature.spawn(i, j);
                         g->add_zombie(creature);
                     }