Alien Egg

Whenever Alien Egg ecomes blocked, put
two facehugger counter on that blocking creature with:"At the beginning of your upkeep, remove a facehugger counter
from that a creature, if that creature has no facehugger counters on it, destroy it and you
create a black Tyranid creature token with:
'At the beginning of your end step, put a
+1/+1 counter on that creature.'"