Colossal Hydra

Trample, haste, protection from spells and planeswalker abilities, X strike
(X is the amount of +1/+1 counters it has)
Colossal Hydra enters the battlefield with X
+1/+1 counters on it.
When Colossal Hydra attacks, double the
+1/+1 counters Colossal Hydra has and
create an exact copy of Colossal Hydra.
If damage is dealt to Colossal Hydra put
X +1/+1 counters on it(X is the amount of
damage dealt).