Volatile Stormdrake

Control-swap creatures have always been paid for by the terms of the trade. Gilded Drake handed the opponent a 3/3 flier of their own and let you choose the creature you got in return, so the exchange was a downgrade dressed up as a steal: you surrendered a body and put the drake into their hands. This design solves that lopsidedness with energy. The swap comes bundled with four energy and a condition: pay the taken creature's mana value in energy or sacrifice it. Four energy covers anything of mana value four or less outright, so most of the creatures worth stealing stay stolen, and the opponent inherits a 3/2 flier you cannot easily reclaim. Bigger targets demand more energy than the card supplies alone, so the effect scales its own leash: the more valuable the theft, the deeper your energy reserves need to be. The protective clause, hexproof from activated and triggered abilities, is narrower than it reads. Hexproof only stops targeting by opponents, so it does nothing about how the new controller treats the creature once the swap resolves. What it guards against, before the exchange, is removal that reaches the drake through an ability: no bouncing it, no shrinking it with a -X/-X trigger. It does not survive a targeted destroy spell cast in response to the enter trigger, and that matters: kill the drake before the exchange resolves and the whole trade evaporates, leaving nothing swapped and no energy gained.