Lethal Vapors + Encroaching Mycosynth + Null Rod

Lethal Vapors

Encroaching Mycosynth

Null Rod

How it works

1. Whenever a creature enters the battlefield, Lethal Vapors triggers, destroying that creature.
2. Because Null Rod prevents Lethal Vapors's activated ability from being activated, it cannot be destroyed due to its ability.

This clever lock relies on reshaping the board's permanents so that Null Rod can muzzle Lethal Vapors's self-destruct hatch. By using Encroaching Mycosynth to turn Lethal Vapors into an artifact, Null Rod's static ability shuts down its `{0}` activation entirely. With players no longer able to pay the cost to destroy the enchantment and skip a turn, Lethal Vapors becomes permanent and un-removable by its own hand, leaving its triggered ability free to automatically and permanently annihilate every single creature that dares enter the battlefield.