Agatha's Soul Cauldron, Scion of the Swarm, and Triskelion

Prerequisites

• Agatha's Soul Cauldron on the battlefield
• Scion of the Swarm on the battlefield
• Triskelion in exile

Steps

1. Activate Scion of the Swarm by using Triskelion's ability by removing a +1/+1 counter from it, dealing 1 damage to any target and causing you to gain 1 life due to its lifelink
2. Scion of the Swarm triggers, putting a +1/+1 counter on it
3. Repeat

Results

• Infinite damage
• Infinite lifegain triggers
• Infinite lifegain