Gxxyu, The Roaring Faces

Energiko (Whenever a card's ability gives this card's controller one or more {e} (energy counters), this creature gains +1/+1 until end of turn.)
{r}{r},{t}: You get {e} (an energy counter).
Pay {e}{e}{e}{e}: Gxxyu deals X amount of damage to target player where X is the number of {e} (energy counters) on that player. That player loses half of that many {e}, rounded down.