Xenomorph Queen

{t}Place egg token on the field with the effect:"Sacrifice token to destroy target creature,put a
4/4 alien token on the field."
{t}{2}Sacrifice this creature.Summon a Xenomorph queen egg with with 3 counters on it.
When a Xenomorph dies,remove or add a counter.When it reaches 0,it becomes a Xenomorph
queen with X +1/+1 counter on it, where X is the power of the last Xenomorph queen.