v2.0.0: added a safety check to Monk Energy gain

core/src/main/java/com/shatteredpixel/shatteredpixeldungeon/actors/buffs/MonkEnergy.java

@@ -134,6 +134,8 @@ public class MonkEnergy extends Buff implements ActionIndicator.Action {
 	}
 
 	public void gainEnergy(Mob enemy ){
+		if (target == null) return;
+
 		if (target.buff(LockedFloor.class) != null && !target.buff(LockedFloor.class).regenOn()){
 			return; //to prevent farming boss minions
 		}