Reduce the toughness of creatures opponents control to 0 on each of your turns
At the beginning of your end step, Toxrill's first ability triggers, putting a slime counter on each creature your opponents control.
Because your opponents' creatures are now 0/0 due to Maha and Toxrill's static effects, the creatures die as a state-based action due to having zero toughness unless there is an effect boosting their toughness.
Repeat during each of your end steps.
Component Cards
How It Works
At the beginning of your end step, Toxrill's first ability triggers, putting a slime counter on each creature your opponents control.
Because your opponents' creatures are now 0/0 due to Maha and Toxrill's static effects, the creatures die as a state-based action due to having zero toughness unless there is an effect boosting their toughness.
Repeat during each of your end steps.