Glen Elendra

At end of combat, you may exchange control of target creature you control that dealt combat damage to a player this combat and target creature that player controls.
Whenever chaos ensues, gain control of target creature you own.

Planechase Anthology Planes

At end of combat, you may exchange control of target creature you control that dealt combat damage to a player this combat and target creature that player controls.
Whenever you roll {Chaos}, gain control of target creature you own.

Planechase 2012 Planes

At end of combat, you may exchange control of target creature you control that dealt combat damage to a player this combat and target creature that player controls.
Whenever you roll chaos, gain control of target creature you own.

If either target is no longer on the battlefield or is otherwise an illegal target when the chaos ability resolves, the exchange won’t happen. No creatures will change controllers. If both targets are illegal, the ability won’t resolve.