Rahab, Angel of the Deep

Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.
Whenever an opponent casts a noncreature spell, you may put a +1+1 counter on Rahab unless that player pays {4}.
At the beginning of your upkeep, you may sacrifice a creature. If you do, return Rahab from your graveyard or exile to your hand.