Savage Vigor Head is a common Elite Creature — Head card from Face the Hydra (TFTH), collector number 3. Current market price: $9.96, TCGplayer market prices via Scryfall.
At the beginning of the Hydra's end step, reveal the top card of the Hydra's library and the Hydra casts that card. Hero's Reward — When Savage Vigor Head leaves the battlefield, each player gains 4 life and draws a card.