Stitched Colossus

Stitched Colossus's power and toughness are equal to the number of Zombies you control.
When Stitched Colossus enters the battlefield, put three 2/2 black Zombie creature tokens onto the battlefield.
Whenever an opponent puts a creature card into his or her graveyard, put a +1/+1 counter on each Zombie creature you control.