Lethal Vapors + Phyrexian Revoker

Lethal Vapors
Phyrexian Revoker

Requires
Lethal Vapors must be on the battlefield. Phyrexian Revoker must be on the battlefield. "Lethal Vapors" chosen with Phyrexian Revoker.
Steps
  1. Whenever a creature enters the battlefield, Lethal Vapors triggers, destroying that creature.
  2. Because Phyrexian Revoker prevents Lethal Vapors's activated ability from being activated, it cannot be destroyed due to its ability.
Results
Destroy all creatures that enter the battlefield.