diff --git a/core/src/com/riiablo/ai/AI.java b/core/src/com/riiablo/ai/AI.java
index be96d8be..161d61ba 100644
--- a/core/src/com/riiablo/ai/AI.java
+++ b/core/src/com/riiablo/ai/AI.java
@@ -1,15 +1,40 @@
 package com.riiablo.ai;
 
+import com.riiablo.codec.Animation;
 import com.riiablo.entity.Monster;
 import com.riiablo.screen.GameScreen;
 
+import org.apache.commons.lang3.ArrayUtils;
+
 public abstract class AI {
   public static final AI IDLE = new Idle();
 
+  protected final float SLEEP;
+  protected final int[] params;
   protected Monster entity;
 
   public AI(Monster entity) {
     this.entity = entity;
+
+    // Special case for Idle AI -- TODO: fix Idle AI to remove this special case
+    if (entity == null) {
+      SLEEP = Float.POSITIVE_INFINITY;
+      params = ArrayUtils.EMPTY_INT_ARRAY;
+      return;
+    }
+
+    // TODO: difficulty-based params
+    params = new int[8];
+    params[0] = entity.monstats.aip1[0];
+    params[1] = entity.monstats.aip2[0];
+    params[2] = entity.monstats.aip3[0];
+    params[3] = entity.monstats.aip4[0];
+    params[4] = entity.monstats.aip5[0];
+    params[5] = entity.monstats.aip6[0];
+    params[6] = entity.monstats.aip7[0];
+    params[7] = entity.monstats.aip8[0];
+
+    SLEEP = Animation.FRAME_DURATION * entity.monstats.aidel[0];
   }
 
   public void interact(GameScreen gameScreen) {}
diff --git a/core/src/com/riiablo/ai/Fallen.java b/core/src/com/riiablo/ai/Fallen.java
index 60129764..c7618a06 100644
--- a/core/src/com/riiablo/ai/Fallen.java
+++ b/core/src/com/riiablo/ai/Fallen.java
@@ -6,7 +6,6 @@ import com.badlogic.gdx.ai.msg.Telegram;
 import com.badlogic.gdx.math.MathUtils;
 import com.badlogic.gdx.math.Vector2;
 import com.riiablo.Riiablo;
-import com.riiablo.codec.Animation;
 import com.riiablo.entity.Entity;
 import com.riiablo.entity.Monster;
 import com.riiablo.entity.Player;
@@ -32,28 +31,12 @@ public class Fallen extends AI {
     }
   }
 
-  private final float SLEEP;
-
-  int[] pa;
   final StateMachine<Monster, State> stateMachine;
   float nextAction;
   float time;
 
   public Fallen(Monster entity) {
     super(entity);
-
-    // TODO: difficulty-based params
-    pa = new int[8];
-    pa[0] = entity.monstats.aip1[0];
-    pa[1] = entity.monstats.aip2[0];
-    pa[2] = entity.monstats.aip3[0];
-    pa[3] = entity.monstats.aip4[0];
-    pa[4] = entity.monstats.aip5[0];
-    pa[5] = entity.monstats.aip6[0];
-    pa[6] = entity.monstats.aip7[0];
-    pa[7] = entity.monstats.aip8[0];
-
-    SLEEP = Animation.FRAME_DURATION * entity.monstats.aidel[0];
     stateMachine = new DefaultStateMachine<>(entity, State.IDLE);
   }
 
@@ -76,12 +59,12 @@ public class Fallen extends AI {
           if (dst < melerng) {
             entity.setPath(null, null);
             stateMachine.changeState(State.ATTACK);
-            entity.sequence(MathUtils.randomBoolean(pa[3] / 100f) ? Monster.MODE_A2 : Monster.MODE_A1, Monster.MODE_NU);
+            entity.sequence(MathUtils.randomBoolean(params[3] / 100f) ? Monster.MODE_A2 : Monster.MODE_A1, Monster.MODE_NU);
             Riiablo.audio.play(entity.monstats.MonSound + "_attack_1", true);
             time = MathUtils.random(1f, 2);
             return;
           } else if (dst < 35) {
-            if (MathUtils.randomBoolean(pa[0] / 100f)) {
+            if (MathUtils.randomBoolean(params[0] / 100f)) {
               entity.setPath(entity.map, ent.position());
               stateMachine.changeState(State.APPROACH);
               return;
diff --git a/core/src/com/riiablo/ai/QuillRat.java b/core/src/com/riiablo/ai/QuillRat.java
index 2a6f2451..85b0b1a5 100644
--- a/core/src/com/riiablo/ai/QuillRat.java
+++ b/core/src/com/riiablo/ai/QuillRat.java
@@ -6,21 +6,8 @@ import com.riiablo.entity.Monster;
 
 public class QuillRat extends AI {
 
-  int[] pa;
-
   public QuillRat(Monster entity) {
     super(entity);
-
-    // TODO: difficulty-based params
-    pa = new int[8];
-    pa[0] = entity.monstats.aip1[0];
-    pa[1] = entity.monstats.aip2[0];
-    pa[2] = entity.monstats.aip3[0];
-    pa[3] = entity.monstats.aip4[0];
-    pa[4] = entity.monstats.aip5[0];
-    pa[5] = entity.monstats.aip6[0];
-    pa[6] = entity.monstats.aip7[0];
-    pa[7] = entity.monstats.aip8[0];
   }
 
   @Override
diff --git a/core/src/com/riiablo/ai/Zombie.java b/core/src/com/riiablo/ai/Zombie.java
index ef6ff648..291b88bc 100644
--- a/core/src/com/riiablo/ai/Zombie.java
+++ b/core/src/com/riiablo/ai/Zombie.java
@@ -6,7 +6,6 @@ import com.badlogic.gdx.ai.msg.Telegram;
 import com.badlogic.gdx.math.MathUtils;
 import com.badlogic.gdx.math.Vector2;
 import com.riiablo.Riiablo;
-import com.riiablo.codec.Animation;
 import com.riiablo.entity.Entity;
 import com.riiablo.entity.Monster;
 import com.riiablo.entity.Player;
@@ -32,28 +31,12 @@ public class Zombie extends AI {
     }
   }
 
-  private final float SLEEP;
-
-  int[] pa;
   final StateMachine<Monster, State> stateMachine;
   float nextAction;
   float time;
 
   public Zombie(Monster entity) {
     super(entity);
-
-    // TODO: difficulty-based params
-    pa = new int[8];
-    pa[0] = entity.monstats.aip1[0];
-    pa[1] = entity.monstats.aip2[0];
-    pa[2] = entity.monstats.aip3[0];
-    pa[3] = entity.monstats.aip4[0];
-    pa[4] = entity.monstats.aip5[0];
-    pa[5] = entity.monstats.aip6[0];
-    pa[6] = entity.monstats.aip7[0];
-    pa[7] = entity.monstats.aip8[0];
-
-    SLEEP = Animation.FRAME_DURATION * entity.monstats.aidel[0];
     stateMachine = new DefaultStateMachine<>(entity, State.IDLE);
   }
 
@@ -76,12 +59,12 @@ public class Zombie extends AI {
           if (dst < melerng) {
             entity.setPath(null, null);
             stateMachine.changeState(State.ATTACK);
-            entity.sequence(MathUtils.randomBoolean(pa[3] / 100f) ? Monster.MODE_A2 : Monster.MODE_A1, Monster.MODE_NU);
+            entity.sequence(MathUtils.randomBoolean(params[3] / 100f) ? Monster.MODE_A2 : Monster.MODE_A1, Monster.MODE_NU);
             Riiablo.audio.play(entity.monstats.MonSound + "_attack_1", true);
             time = MathUtils.random(1f, 2);
             return;
-          } else if (dst < pa[1]) {
-            if (MathUtils.randomBoolean(pa[0] / 100f)) {
+          } else if (dst < params[1]) {
+            if (MathUtils.randomBoolean(params[0] / 100f)) {
               entity.setPath(entity.map, ent.position());
               stateMachine.changeState(State.APPROACH);
               return;