Aether Adjustment

Enchant creature you control
When Aether Adjustment enters the battlefield you may pay {e}{e}. If you do you get {e}{e}, if you don't sacrifice it.
Enchanted creature gets +1/+1 and "pay {e}: this creature can't be blocked this turn or when this creature deals combat damage to a player draw a card or exile this creature then return it to the battlefield under your control."