Thornbite Staff, Arcane Teachings, and Basilisk Collar

Prerequisites

• Thornbite Staff on the battlefield
• Arcane Teachings on the battlefield
• Basilisk Collar on the battlefield
• All permanents attached to the same creature
• The creature does not have summoning sickness

Steps

1. Activate the creature by tapping it, dealing 1 damage to any opponent's creature and causing you to gain 1 life
2. The opponent's creature dies due to deathtouch, triggering Thornbite Staff, untapping your creature
3. Repeat

Results

• Destroy all creatures opponents control
• Destroy all creatures opponents control whenever a creature enters the battlefield