Bone Hydra

Bone Hydra enters the battlefield with 3 +1/+1 counters on it. Whenever a +1/+1 counter is placed on Bone Hydra, it deals damage equal to the number of +1/+1 counters on it to target creature.
{4}, exile a card from your graveyard: Put a +1/+1 counter on Bone Hydra.