Toxrill, Caustic Calamity

At the beginning of every end step place a -1/-1 counter on each creature your opponents control.
Whenever a creature with a -1/-1 counter dies
place a +1/+1 counter on Toxrill, Caustic
Calamity.
{g/u}{u/b}{t} - Remove any amount of +1/+1 counters
from Toxrill, Caustic Calamity and draw that
many cards. As an additional cost to activate this ability, sacrifice and nonland permanent.
Activate only as a sorcery.