Toothy, Imaginary Friend

Partner with Pir, Imaginative Rascal (When this creature enters the battlefield, target player may put
Pir into their hand from their library, then shuffle.)
Whenever you draw a card, put a +1/+1
counter on Toothy, Imaginary Friend.
When Toothy leaves the battlefield, draw a
card for each +1/+1 counter on it.