Mindslaver is a mythic Legendary Artifact card from Scars of Mirrodin (SOM), collector number 176. Current market price: $4.51 (foil $30.20), TCGplayer market prices via Scryfall.
{4}, {T}, Sacrifice Mindslaver: You control target player during that player's next turn. (You see all cards that player could see and make all decisions for them.)