When Time Elemental attacks or blocks, at end of combat, sacrifice it and it deals 5 damage to you. {2}{U}{U}, {T}: Return target permanent that isn't enchanted to its owner's hand.
2004-10-04
You both sacrifice it and deal the 5 damage at end of combat.
2005-08-01
A "permanent that isn't enchanted" is a permanent with no Auras on it.
2007-09-16
If Time Elemental attacks or blocks, but you no longer control it at end of combat, you can't sacrifice it. However, it will still deal 5 damage to you.