Encroaching Mycosynth + Lethal Vapors + Null Rod

UB identity

Commander legal

The 3 combo pieces

• Encroaching Mycosynth
• Lethal Vapors
• Null Rod

How to execute it

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.

What the combo produces

• Destroy all creatures that enter the battlefield
• Lock