Enchantment, 3R (4) Whenever a creature comes into play, that creature's controller may have it deal damage equal to its power to target creature or player of his or her choice. "If we cannot live proudly, we die so!" —Eladamri, Lord of Leaves
Illus. Pete Venters
10/4/2004: The triggered ability does not check the creature's power until the ability resolves. If the creature is not in play when the ability resolves, it does damage equal to the power of the creature right before it left play. This means that if a creature comes into play which can destroy itself as a "comes into play" ability, the order of resolution of the triggered abilities does not matter.
9/25/2006: If Player A controls Pandemonium when a creature comes into play 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.