Skullbriar, the Walking Grave is a rare Legendary Creature — Zombie Elemental card from The List (PLST), collector number CMD-227. Current market price: $1.92, TCGplayer market prices via Scryfall.
Haste Whenever Skullbriar deals combat damage to a player, put a +1/+1 counter on it. Counters remain on Skullbriar as it moves to any zone other than a player's hand or library.