Anti-Venom, Horrifying Healer + Agatha's Soul Cauldron + Corpsejack Menace + Deathbringer Thoctar

Anti-Venom, Horrifying Healer

Agatha's Soul Cauldron

Corpsejack Menace

Deathbringer Thoctar

How it works

1. Activate Anti-Venom using Deathbringer Thoctar's ability by removing a +1/+1 counter from it, targeting itself and putting two +1/+1 counters on it due to its replacement effect and Corpsejack Menace.
2. Activate Anti-Venom using Deathbringer Thoctar's ability by removing a +1/+1 counter from it, dealing 1 damage to any target.
3. Repeat.

This ingenious loop centers around Agatha's Soul Cauldron, which feeds Deathbringer Thoctar's activated abilities to Anti-Venom, Horrifying Healer after Deathbringer Thoctar is exiled into it. With Corpsejack Menace doubling every counter placed, Anti-Venom, Horrifying Healer turns its own damage prevention into a surplus of growth. By removing a counter to deal damage and then using the Cauldron-granted ability to trigger the prevention clause and gain more counters than you started with, you generate an explosive, self-sustaining cascade of infinite damage and growth.