Palthoc, Maw of the Sea

{2}{u}, {t}: Exile target nonland permanent. As
long as it remains exiled, its controller may cast
it from exile by paying its mana cost plus {3}.
On each of your upkeeps, put a digestion counter
on each creature card exiled with Palthoc, Maw
of the Sea.
Any creature card with four or more digestion
counters on it cannot be cast from exile.