Warren Instigator is a mythic Creature — Goblin Berserker card from Duel Decks: Merfolk vs. Goblins (DDT), collector number 32. Current market price: — (foil $18.12), TCGplayer market prices via Scryfall.
Double strike Whenever this creature deals damage to an opponent, you may put a Goblin creature card from your hand onto the battlefield.