Darksteel Mutation is a uncommon Enchantment — Aura card from The List (PLST), collector number CMA-9. Current market price: $1.67, TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature is an Insect artifact creature with base power and toughness 0/1 and has indestructible, and it loses all other abilities, card types, and creature types.