Rampaging Dreadwolf

Trample, Haste
At the beginning of your end step, put a charge counter on Rampaging Dreadwolf, then if it has four or mote charge counters on it, sacrifice it unless you pay {r}{g}, if you don't, discard a card and this creature deals 2 damage to target creature.
Don't kill it, it kills you. Kill it, it kills you.