Augath Hydra

At the beginning of each of your end steps, put
X +1/+1 counters on Augath Hydra.
Remove a +1/+1 counter from Augath Hydra: Put a +1/+1 counter on another target creature.
{g}{g}{g}, {t}: Double the amount of +1/+1 counters
on Augath Hydra.