Ulvenwald Hydra is a mythic Creature — Hydra card from Shadows over Innistrad (SOI), collector number 235. Current market price: $0.76 (foil $4.62), TCGplayer market prices via Scryfall.
Reach Ulvenwald Hydra's power and toughness are each equal to the number of lands you control. When this creature enters, you may search your library for a land card, put it onto the battlefield tapped, then shuffle.