Ukkima, Stalking Shadow is a mythic Legendary Creature — Whale Wolf card from Outlaws of Thunder Junction Commander (OTC), collector number 247. Current market price: $0.41, TCGplayer market prices via Scryfall.
Partner with Cazur, Ruthless Stalker (When this creature enters, target player may put Cazur into their hand from their library, then shuffle.) Ukkima can't be blocked. When Ukkima leaves the battlefield, it deals X damage to target player and you gain X life, where X is its power.