Xenorek, Rakdos Archdemon

Flying, Trample
Whenever Xenorek, Rakdos Archdemon deals combat damage to a player, put a +1/+1 counter on this creature.
On each of your combat steps, if there are five or
more +1/+1 counters on Xenorek, Rakdos
Archdemon, take an extra combat step.