diff --git a/forge-game/src/main/java/forge/game/card/CardFactoryUtil.java b/forge-game/src/main/java/forge/game/card/CardFactoryUtil.java
index a583250c15d..8bab7a0c324 100644
--- a/forge-game/src/main/java/forge/game/card/CardFactoryUtil.java
+++ b/forge-game/src/main/java/forge/game/card/CardFactoryUtil.java
@@ -719,10 +719,13 @@ public class CardFactoryUtil {
             return c.getImprintedCards().get(0).getCMC();
         }
 
-        if (l[0].startsWith("GreatestPower_")) {
-            final String restriction = l[0].substring(14);
-            final String[] rest = restriction.split(",");
-            CardCollection list = CardLists.getValidCards(cc.getGame().getCardsIn(ZoneType.Battlefield), rest, cc, c, null);
+        if (l[0].startsWith("GreatestPower")) {
+            final String[] lparts = l[0].split("_", 2);
+            final String[] rest = lparts[1].split(",");
+            final CardCollectionView cardsInZones = lparts[0].length() > 13
+                    ? game.getCardsIn(ZoneType.listValueOf(lparts[0].substring(13)))
+                    : game.getCardsIn(ZoneType.Battlefield);
+            CardCollection list = CardLists.getValidCards(cardsInZones, rest, cc, c, null);
             int highest = 0;
             for (final Card crd : list) {
                 if (crd.getNetPower() > highest) {
diff --git a/forge-gui/res/cardsfolder/upcoming/carrion_grub.txt b/forge-gui/res/cardsfolder/upcoming/carrion_grub.txt
new file mode 100644
index 00000000000..6495bda95bb
--- /dev/null
+++ b/forge-gui/res/cardsfolder/upcoming/carrion_grub.txt
@@ -0,0 +1,10 @@
+Name:Carrion Grub
+ManaCost:3 B
+Types:Creature Insect
+PT:0/5
+S:Mode$ Continuous | Affected$ Card.Self | AddPower$ X | References$ X | Description$ CARDNAME gets +X/+0, where X is the greatest power among creature cards in your graveyard.
+SVar:X:Count$GreatestPowerGraveyard_Creature.YouOwn
+T:Mode$ ChangesZone | Origin$ Any | Destination$ Battlefield | ValidCard$ Card.Self | Execute$ TrigMill | TriggerDescription$ When CARDNAME enters the battlefield, mill four cards.
+SVar:TrigMill:DB$ Mill | Defined$ You | NumCards$ 4
+DeckHas:Ability$Graveyard
+Oracle:Carrion Grub gets +X/+0, where X is the greatest power among creature cards in your graveyard.\nWhen Carrion Grub enters the battlefield, mill four cards. (Put the top four cards of your library into your graveyard.)