Gilded Drake

The cleanest theft Magic has printed: the body is a fig leaf, and the trade is the whole card. Control-exchange effects had always been clunky (Donate needed a second card to be worth anything, the various mind-control auras left you down a card if the creature died), but the design here folds the entire transaction into a single enters trigger and forces it to resolve. The "if you don't or can't make an exchange, sacrifice this creature" clause is the discipline that makes the price work: you cannot bank the Drake as a 3/3 flier and hold the swap for later, so the card is never a creature you keep. What you hand over is the catch, and the catch is real: a 3/3 flier is a meaningful gift if the opponent has nothing worth taking, which is why the "up to one" lets it eat itself rather than donate a beater for free. The piece players actually exploit is permanence. Unlike Act of Treason effects, there is no return clause and no end-step handback; the exchange of control is forever. Steal the threat, and it stays stolen. The drawback only bites if your opponent has nothing you would rather own than your own Drake, and against the right target the 3/3 you surrender is a rounding error. It is theft dressed as a creature, and the creature was only ever the receipt.