Vitae Collector

Mutate 1 (If this creature would untap during your untap step, you may instead put a +1/+1 counter on
it.)
Whenever Vitae Collector mutates, each opponent loses 1 life and you gain 1 life.
Just as farmers fatten their block in preparation for the slaughter, so too do the Collectors ensure that their victims' blood is rich in the hormones of fear before exsanguination.