Shambling Shell is a common Creature — Plant Zombie card from GRN Guild Kit (GK1), collector number 70. Current market price: $0.18, TCGplayer market prices via Scryfall.
Sacrifice this creature: Put a +1/+1 counter on target creature. Dredge 3 (If you would draw a card, you may mill three cards instead. If you do, return this card from your graveyard to your hand.)