Emiel 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.
({g/w} can be paid with either {g} or {w}.)