Garrett, Keeper Freelancer

{0}: Exile target nonland card from an opponent's
graveyard that was milled this turn. You may cast
it as long as that card remains exiled and you may
spend mana as though it were mana of any type
to cast that spell. Activate this ability only once
each turn.
Remove Garrett, Keeper Freelancer from
combat, {2}{u}: Target player mills two cards. Tap
Garrett, Keeper Agent.