Agatha's Soul Cauldron + Spike Feeder + Karlov of the Ghost Council

Agatha's Soul Cauldron

Spike Feeder

Karlov of the Ghost Council

How it works

1. Activate Karlov of the Ghost Council using Spike Feeder's second ability by removing a +1/+1 counter from it, causing you to gain 2 life.
2. Karlov of the Ghost Council triggers, putting two +1/+1 counters on it.
3. Repeat.

This clever loop comes together by using Agatha's Soul Cauldron to grant Spike Feeder's activated life-gain ability to Karlov of the Ghost Council, letting Karlov tap into that lifegain engine directly. Whenever you remove a +1/+1 counter from Spike Feeder to gain 2 life, Karlov of the Ghost Council triggers to receive two fresh +1/+1 counters. Because this net gain of counters outpaces the cost, you can repeat the process indefinitely to generate infinite life and endlessly pump your creatures' power and toughness.