Mark of Mutiny

The +1/+1 counter is the tell. Most one-turn steal effects in this family (Threaten, Act of Treason) hand the creature back exactly as they found it: you swing once, the loan expires, and the board is unchanged except for the damage the attacker dealt. This version untaps the creature, grants it haste, and slips a permanent +1/+1 counter onto it before the lease runs out. That counter is the only thing that survives the end-of-turn return, and it survives in the wrong direction: even after the borrowed attacker walks home, your opponent's blocker is now a point bigger and pointed back at you. You have spent a card to deal combat damage and to permanently improve a creature you don't keep. That is the genuine trade buried in the design, and it is the same three mana () as the rivals that leave no mark at all. The sorcery-speed clause is doing the rest of the balancing: no instant-speed ambush, no surprise alpha strike off an untap, just a declared offensive commitment on your own turn with the haste there to make the rental worth declaring. The sacrifice-outlet line (take it, swing, eat it before it returns) reads like the headline interaction, but it is no different here than with any steal spell; the counter is the only thing that distinguishes this one, and whether it helps or hurts depends entirely on whether the creature comes back.