Imperceptible Parasite

As an additional cost to cast this card sacrifice an
Egg token.
Enchant target creature, enchanted creature gets
a -1/-1 counter during each players end step.
When Enchanted creature dies create a token
copy of that creature under your control, it's a Xenomorph in addition to it's other types.
You may pay {5} to put Imperceptible Parasite
back into your hand from the graveyard. When it enters the graveyard for a second time exile
it instead.