Darksteel Sentinel (TD2-016) [Duel Decks: Mirrodin Pure vs. New Phyrexia]

Flash (You may cast this spell any time you could cast an instant.)
Vigilance
Indestructible (Damage and effects that say "destroy" don't destroy this creature. If its toughness is 0 or less, it's still put into its owner's graveyard.)