Deathbringer Thoctar, and Basilisk Collar

Prerequisites

• Deathbringer Thoctar on the battlefield
• Basilisk Collar on the battlefield
• Deathbringer Thoctar has at least one +1/+1 counter on it
• Basilisk Collar attached to Deathbringer Thoctar

Steps

1. Activate Deathbringer Thoctar by removing a +1/+1 counter from it, dealing 1 damage to any creature an opponent controls and causing you to gain 1 life
2. The creature dies as a state-based action due to Deathbringer Thoctar's deathtouch
3. Deathbringer Thoctar triggers, putting a +1/+1 counter on itself
4. Repeat as desired
5. You may also repeat this combo whenever a creature enters the battlefield under an opponent's control

Results

• Destroy all creatures opponents control
• Destroy any creature that enters the battlefield under an opponent's control