The Master, Transcendent is a mythic Legendary Artifact Creature — Mutant card from Fallout (PIP), collector number 419. Current market price: $2.65 (foil $2.31), TCGplayer market prices via Scryfall.
When The Master enters, target player gets two rad counters. {T}: Put target creature card in a graveyard that was milled this turn onto the battlefield under your control. It's a green Mutant with base power and toughness 3/3. (It loses its other colors and creature types.)