Shadowfax the Blessed

{3}: Exile another target creature you control, then return it to the battlefield under its owner’s control.
Whenever another creature enters the battlefield under your control, you may pay {g/w}. If
you do, put a +1/+1 counter on it. If it’s a Unicorn, put two +1/+1 counters on it instead.

“Shadowfax, show us the meaning of haste”
- Gandalf