Secret of Bloodbending is a mythic Sorcery — Lesson card from Avatar: The Last Airbender (TLA), collector number 69. Current market price: $1.02 (foil $1.50), TCGplayer market prices via Scryfall.
As an additional cost to cast this spell, you may waterbend {10}. You control target opponent during their next combat phase. If this spell's additional cost was paid, you control that player during their next turn instead. (You see all cards that player could see and make all decisions for them.) Exile Secret of Bloodbending.