Darksteel Hydra is a mythic Artifact Creature — Phyrexian Hydra card from Alchemy: Phyrexia (YONE), collector number 20.
Indestructible Darksteel Hydra enters with X oil counters on it. Darksteel Hydra's power and toughness are each equal to twice the number of oil counters on it. When Darksteel Hydra enters, conjure a card named Darksteel Ingot and a card named Darksteel Plate into your hand.