The Ocean of Ick

This card enters the battlefield tapped unless you control a Pet
{t}: Add {u} or {g} to your mana pool.
The Ocean of Ick is a mystical mass of magic and
water with timeless mysteries that lie just beneath the
waves, legends circulate of enormous, cat-faced serpents
devouring fishing boats and galleons in equal measure,
yet they also speak of ancient treasures and blessed
pools deep in underwater coves and drowned caverns.