The Eternal Registeel

+4: This permanent deals 5 damage to target creature or planeswalker and loses this ability.
0: Untap up to two target artifacts. Registeel gains "+4: Registeel deals 5 damage to target creature or planeswalker and loses this ability."
-16: Sacrifice any number of noncreature permanents. Registeel deals four times that much damage to each opponent.