Think its fixed now

src/me/libraryaddict/disguise/LibsDisguises.java

@@ -219,6 +219,7 @@ public class LibsDisguises extends JavaPlugin {
                     ((Zombie) bukkitEntity).setBaby(true);
                     disguiseValues.setBabyBox(ReflectionManager.getBoundingBox(bukkitEntity));
                 }
+                disguiseValues.setEntitySize(ReflectionManager.getSize(bukkitEntity));
             } catch (Exception ex) {
                 System.out.print("[LibsDisguises] Uh oh! Trouble while making values for the disguise " + disguiseType.name()
                         + "!");

src/me/libraryaddict/disguise/utilities/DisguiseUtilities.java

@@ -153,9 +153,9 @@ public class DisguiseUtilities {
                 }
             }
             if (isDisguiseInUse(disguise)) {
-                ReflectionManager.setBoundingBox(entity, entityBox, disguiseBox);
+                ReflectionManager.setBoundingBox(entity, entityBox, disguiseBox, disguiseValues.getEntitySize());
             } else {
-                ReflectionManager.setBoundingBox(entity, disguiseBox, entityBox);
+                ReflectionManager.setBoundingBox(entity, disguiseBox, entityBox, entityValues.getEntitySize());
             }
         }
     }

src/me/libraryaddict/disguise/utilities/DisguiseValues.java

@@ -45,6 +45,7 @@ public class DisguiseValues {
 
     private FakeBoundingBox adultBox;
     private FakeBoundingBox babyBox;
+    private float[] entitySize;
     private int enumEntitySize;
     private HashMap<Integer, Object> metaValues = new HashMap<Integer, Object>();
     private Class nmsEntityClass;
@@ -63,6 +64,10 @@ public class DisguiseValues {
         return babyBox;
     }
 
+    public float[] getEntitySize() {
+        return entitySize;
+    }
+
     public int getEntitySize(double paramDouble) {
         double d = paramDouble - (((int) Math.floor(paramDouble)) + 0.5D);
 
@@ -123,6 +128,10 @@ public class DisguiseValues {
         babyBox = newBox;
     }
 
+    public void setEntitySize(float[] size) {
+        this.entitySize = size;
+    }
+
     public void setMetaValue(int no, Object value) {
         metaValues.put(no, value);
     }

src/me/libraryaddict/disguise/utilities/FakeBoundingBox.java

@@ -12,15 +12,15 @@ public class FakeBoundingBox {
     }
 
     public double getX() {
-        return xMod / 2;
+        return xMod;
     }
 
     public double getY() {
-        return yMod / 2;
+        return yMod;
     }
 
     public double getZ() {
-        return zMod / 2;
+        return zMod;
     }
 
 }

src/me/libraryaddict/disguise/utilities/ReflectionManager.java

@@ -9,7 +9,6 @@ import org.bukkit.Bukkit;
 import org.bukkit.Sound;
 import org.bukkit.World;
 import org.bukkit.entity.Entity;
-import org.bukkit.entity.EntityType;
 import org.bukkit.inventory.ItemStack;
 
 public class ReflectionManager {
@@ -215,6 +214,18 @@ public class ReflectionManager {
         return null;
     }
 
+    public static float[] getSize(Entity entity) {
+        try {
+            float length = getNmsClass("Entity").getField("length").getFloat(getNmsEntity(entity));
+            float width = getNmsClass("Entity").getField("width").getFloat(getNmsEntity(entity));
+            float height = getNmsClass("Entity").getField("height").getFloat(getNmsEntity(entity));
+            return new float[] { length, width, height };
+        } catch (Exception ex) {
+            ex.printStackTrace();
+        }
+        return null;
+    }
+
     public static Float getSoundModifier(Object entity) {
         try {
             soundMethod.setAccessible(true);
@@ -237,7 +248,7 @@ public class ReflectionManager {
         return after17;
     }
 
-    public static void setBoundingBox(Entity entity, FakeBoundingBox oldBox, FakeBoundingBox newBox) {
+    public static void setBoundingBox(Entity entity, FakeBoundingBox oldBox, FakeBoundingBox newBox, float[] entitySize) {
         try {
             Object boundingBox = getNmsClass("Entity").getField("boundingBox").get(getNmsEntity(entity));
             int stage = 0;
@@ -247,16 +258,16 @@ public class ReflectionManager {
                     stage++;
                     switch (stage) {
                     case 1:
-                        x = field.getDouble(boundingBox) + oldBox.getX();
+                        x = field.getDouble(boundingBox); //+ oldBox.getX();
-                        field.setDouble(boundingBox, x - newBox.getX());
+                 //       field.setDouble(boundingBox, x - newBox.getX());
                         break;
                     case 2:
-                        y = field.getDouble(boundingBox) + oldBox.getY();
+                        y = field.getDouble(boundingBox);// + oldBox.getY();
-                        field.setDouble(boundingBox, y - newBox.getY());
+                   //     field.setDouble(boundingBox, y - newBox.getY());
                         break;
                     case 3:
-                        z = field.getDouble(boundingBox) + oldBox.getZ();
+                        z = field.getDouble(boundingBox); //+ oldBox.getZ();
-                        field.setDouble(boundingBox, z - newBox.getZ());
+                   //     field.setDouble(boundingBox, z - newBox.getZ());
                         break;
                     case 4:
                         field.setDouble(boundingBox, x + newBox.getX());
@@ -272,10 +283,17 @@ public class ReflectionManager {
                     }
                 }
             }
-            if (entity.getType() != EntityType.PLAYER) {
+            setSize(entity, entitySize);
-                // entity.teleport(entity.getLocation().clone()
+        } catch (Exception ex) {
-                // .subtract(oldBox.getX() - newBox.getX(), oldBox.getY() - newBox.getY(), oldBox.getZ() - newBox.getZ()));
+            ex.printStackTrace();
-            }
+        }
+    }
+
+    public static void setSize(Entity entity, float[] size) {
+        try {
+            getNmsClass("Entity").getField("length").setFloat(getNmsEntity(entity), size[0]);
+            getNmsClass("Entity").getField("width").setFloat(getNmsEntity(entity), size[1]);
+            getNmsClass("Entity").getField("height").setFloat(getNmsEntity(entity), size[2]);
         } catch (Exception ex) {
             ex.printStackTrace();
         }