Shambling Shell is a common Creature — Plant Zombie card from The List (PLST), collector number RAV-230. Current market price: $0.29, 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.)