null check in mobAI

src/engine/mobileAI/MobAI.java

@@ -109,7 +109,7 @@ public class MobAI {
                 return;
             }
 
-            if (mob.behaviourType.callsForHelp)
+            if (mob.behaviourType != null && mob.behaviourType.callsForHelp)
                 mobCallForHelp(mob);
 
             if (!MovementUtilities.inRangeDropAggro(mob, target)) {