Slave of Bolas is a uncommon Sorcery card from Duel Decks: Ajani vs. Nicol Bolas (DDH), collector number 67. Current market price: $0.35, TCGplayer market prices via Scryfall.
Gain control of target creature. Untap that creature. It gains haste until end of turn. Sacrifice it at the beginning of the next end step.