Hellspawn Hydra

Supremacy X (When you cast this creature you may pay an additional {x}, if you do, this creature enters the battlefield with X +1/+1 counters on it.)
{1}{g}: Put a +1/+1 counter on Hellspawn Hydra. Then, Hellspawn Hydra deals 2 damage to target creature you control.
As long as Hellspawn Hydra has ten or more +1/+1 counters on it, it has double strike and trample.