Agatha's Soul Cauldron, Spike Feeder, and Bloodbond Vampire

Prerequisites

• Agatha's Soul Cauldron on the battlefield
• Spike Feeder in exile
• Bloodbond Vampire on the battlefield

Steps

1. Activate Bloodbond Vampire using Spike Feeder's second ability by removing a +1/+1 counter from it, causing you to gain 2 life
2. Bloodbond Vampire triggers, putting a +1/+1 counter on it
3. Repeat

Results

• Infinite lifegain
• Infinite lifegain triggers