diff --git a/src/gamedata/g_mapinfo.h b/src/gamedata/g_mapinfo.h
index 560085c73..9f7472854 100644
--- a/src/gamedata/g_mapinfo.h
+++ b/src/gamedata/g_mapinfo.h
@@ -259,6 +259,7 @@ enum ELevelFlags : unsigned int
 	LEVEL3_E4M6SPECIAL			= 0x00008000,
 	LEVEL3_NOSHADOWMAP			= 0x00010000,	// disables shadowmaps for a given level.
 	LEVEL3_AVOIDMELEE			= 0x00020000,	// global flag needed for proper MBF support.
+	LEVEL3_NOJUMPDOWN			= 0x00040000,	// only for MBF21. Inverse of MBF's dog_jumping flag.
 };
 
 
diff --git a/src/playsim/p_enemy.cpp b/src/playsim/p_enemy.cpp
index 528e2b37d..baa97f83c 100644
--- a/src/playsim/p_enemy.cpp
+++ b/src/playsim/p_enemy.cpp
@@ -456,7 +456,7 @@ int P_Move (AActor *actor)
 	// and only if the target is immediately on the other side of the line.
 	AActor *target = actor->target;
 
-	if ((actor->flags6 & MF6_JUMPDOWN) && target &&
+	if ((actor->flags6 & MF6_JUMPDOWN) && target && !(actor->Level->flags3 & LEVEL3_NOJUMPDOWN) &&
 			!(target->IsFriend(actor)) &&
 			actor->Distance2D(target) < 144 &&
 			pr_dropoff() < 235)