Xenomorph Queen

At the beginning of each end step, put a gestation counter on each creature you don't control.

Creatures you don't control get -1/-1 for each gestation counter on them.

Whenever a creature you don't control with a gestation counter on it dies, create a 1/1 black Xenomorph creature token.

{u}{b}, Sacrifice a Xenomorph: Draw a card.