If one of the creatures is an illegal target when the ability resolves, the exchange won’t happen. If both creatures are illegal targets, the ability won’t resolve.
17-10-2013
wotc
If the same player controls both creatures when the ability resolves, nothing happens.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.