Horobi, Death's Wail, Thornbite Staff, and Crenellated Wall

Prerequisites

• Horobi, Death's Wail on the battlefield
• Thornbite Staff on the battlefield
• Crenellated Wall on the battlefield
• Thornbite Staff attached to Crenellated Wall
• Crenellated Wall does not have summoning sickness

Steps

1. Activate Crenellated Wall by tapping it, targeting any creature
2. Horobi triggers, destroying that creature
3. When the creature dies, Crenellated Wall triggers, untapping itself
4. Repeat
5. You may also repeat this loop whenever a creature enters the battlefield under an opponent's control

Results

• Destroy all creatures that enter the battlefield under an opponent's control
• Destroy any number of creatures opponents control