diff --git a/Mage.Sets/src/mage/cards/s/SkeletalSwarming.java b/Mage.Sets/src/mage/cards/s/SkeletalSwarming.java
index b091a84e19e..f4b25ce6b51 100644
--- a/Mage.Sets/src/mage/cards/s/SkeletalSwarming.java
+++ b/Mage.Sets/src/mage/cards/s/SkeletalSwarming.java
@@ -35,7 +35,9 @@ public final class SkeletalSwarming extends CardImpl {
 
     private static final FilterPermanent filter = new FilterControlledPermanent(SubType.SKELETON);
     private static final FilterCreaturePermanent filter2 = new FilterCreaturePermanent(SubType.SKELETON, "");
-    private static final DynamicValue xValue = new AdditiveDynamicValue(new PermanentsOnBattlefieldCount(), StaticValue.get(-1));
+    private static final DynamicValue xValue = new AdditiveDynamicValue(
+            new PermanentsOnBattlefieldCount(filter), StaticValue.get(-1)
+    );
 
     public SkeletalSwarming(UUID ownerId, CardSetInfo setInfo) {
         super(ownerId, setInfo, new CardType[]{CardType.ENCHANTMENT}, "{3}{B}{G}");
@@ -46,7 +48,7 @@ public final class SkeletalSwarming extends CardImpl {
         ).setText("each Skeleton you control has trample"));
         ability.addEffect(new AttacksIfAbleAllEffect(filter2).setText(", attacks each combat if able"));
         ability.addEffect(new BoostControlledEffect(
-                xValue, xValue, Duration.WhileOnBattlefield, filter2, false
+                xValue, StaticValue.get(0), Duration.WhileOnBattlefield, filter2, false
         ).setText(", and gets +X/+0, where X is the number of other Skeletons you control"));
         this.addAbility(ability);