Ob Grunifix, Sea Tyrant

Ob Grunifix can't be blocked by creature with
power equal to or less than the number of flood counters on Ob Grunifix.
Whenever you cast a blue spell, put a flood
counter on Ob Grunifix, then you may return
target nonland permanent with converted mana
cost equal to or less than the number of flood counters on Ob Grunifix, to its owner's hand.