Undying Rage is a uncommon Enchantment — Aura card from Duel Decks: Heroes vs. Monsters (DDL), collector number 26. Current market price: $0.35, TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature gets +2/+2 and can't block. When this Aura is put into a graveyard from the battlefield, return it to its owner's hand.