Endbringer, and Thornbite Staff

Prerequisites

• Endbringer on the battlefield
• Thornbite Staff on the battlefield
• Thornbite Staff attached to Endbringer
• Endbringer does not have summoning sickness
• You have a way to give Endbringer deathtouch

Steps

1. Give Endbringer deathtouch, if needed
2. Activate Endbringer's first ability by tapping it, dealing 1 damage to an opponent's creature and destroying it due to Endbringer's deathtouch
3. When the creature dies, Endbringer triggers, untapping itself
4. Repeat from step 2
5. You may also repeat this loop whenever a creature enters the battlefield under an opponent's control if you have a way to give Endbringer deathtouch indefinitely

Results

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