Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Haste (This creature can attack and as soon as it comes under your control.)

At the beginning of the end step, sacrifice this creature.

Protean Hydra enters with X +1/+1 counters on it.

If damage would be dealt to Protean Hydra, prevent that damage and remove that many +1/+1 counters from it.

Whenever a +1/+1 counter is removed from Protean Hydra, put two +1/+1 counters on it at the beginning of the next end step.