Ralus, Evergrowing Nightmare

Flying, lifelink
Ralus enters the battlefield with X +1/+1
counters on it.
At the beginning of your upkeep you may double
the number of +1/+1 counters on Ralus. If you
do, you lose 3 life and discard a card.
"I will grow, strength and size, I will grow, to cause
your demise."