Mage of Oceans

When Mage of Oceans enters the battlefield, tap
target creature and put a -1/-1 counter on it. It
doesn't untap during that opponent's next untap
step.
When you have 5 or more instants or sorceries in
your graveyard, each opponent discards a card.
Draw cards equal to the number of cards
discarded this way. Until you have 7 or less cards
in your hand, you have no maximum hand size.
You can only use this ability once