Agatha's Soul Cauldron + Spike Feeder + Celestial Unicorn

Agatha's Soul Cauldron

Spike Feeder

Celestial Unicorn

How it works

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

This clever engine transforms Spike Feeder into a self-sustaining lifegain loop by using Agatha's Soul Cauldron to grant its counter-removal ability to Celestial Unicorn. With the Cauldron's color-fixing mana flexibility helping set the board, you can remove a counter from Spike Feeder to gain 2 life, which triggers Celestial Unicorn to regain the counter it just lost. Because Spike Feeder’s ability doesn't require tapping, you can repeat this cycle infinitely to generate boundless life and trigger any associated abilities.