Possess

Certain spells and items allow a player to Possess a target, allowing the player to see through its eyes and control its actions as though the target were the player. As of WoW 2.3, the main action bar changes to reflect the available abilities of the target. Prior to v2.3, the player gained the target's actions via the pet bar.
Examples:
* Mind Control
* Eyes of the Beast
* Various quest items
* The Chess Event in Karazhan