Sleeping Hydra

Sleeping Hydra enters the battlefield tapped with X +1/+1 counters on it and X sleeping counters on it.
Sleeping Hydra does not untap during your
untap step as long as there is sleeping counters on it.
Whenever you cast a spell with X in its cost, remove
X sleeping counters on Sleeping Hydra. At the beginning of your end step remove a sleeping
counter from Sleeping Hydra