Xantcha, Sleeper Agent is a rare Legendary Creature — Phyrexian Minion card from The List (PLST), collector number C18-50. Current market price: $4.28, TCGplayer market prices via Scryfall.
Xantcha enters under the control of an opponent of your choice. Xantcha attacks each combat if able and can't attack its owner or planeswalkers its owner controls. {3}: Xantcha's controller loses 2 life and you draw a card. Any player may activate this ability.