Feral Pursuer

Frantic (As you cast this spell, you may exile up to
X cards from the top of your library, where X is the
amount of generic mana in this spell's mana value.
This spell costs {1} less for each card exiled this way.)
At the beginning of your end step, you may
return a creature card you own in exile to your graveyard. If you do, put a +1/+1 counter on
Feral Pursuer.