Pandemonium | Magic: The Gathering
Formats Pandemonium is Legal in
Official Oracle Text for Pandemonium
—Eladamri, Lord of Leaves
Official Rulings for Pandemonium
9/25/2006 : If player A controls Pandemonium when a creature enters the battlefield under player B's control, player A controls the triggered ability even though player B chooses the target and chooses whether to have the creature deal damage, which could be important if multiple abilities controlled by multiple players trigger.