Gilded Drake
Creature — Drake
Flying
When this creature enters, exchange control of this creature and up to one target creature an opponent controls. If you don't or can't make an exchange, sacrifice this creature. This ability still resolves if its target becomes illegal.
Buyer beware.
Bob Eggleton
Urza's Saga (USG)
• #76Rulings
If the chosen creature to exchange is not on the battlefield at resolution, then sacrifice this card.
(wotc • 2004-10-04)
This ability is targeted, so Protection can prevent targeting if it exists when the ability would be put on the stack. Once the ability is on the stack, adding Protection will not counter the ability but the exchange will not take place since the target is illegal and you sacrifice this card on resolution.
(wotc • 2004-10-04)
Rulings
If the chosen creature to exchange is not on the battlefield at resolution, then sacrifice this card.
(wotc • 2004-10-04)
This ability is targeted, so Protection can prevent targeting if it exists when the ability would be put on the stack. Once the ability is on the stack, adding Protection will not counter the ability but the exchange will not take place since the target is illegal and you sacrifice this card on resolution.
(wotc • 2004-10-04)