Anti-Venom, Horrifying Healer + Agatha's Soul Cauldron + Branching Evolution + Deathbringer Thoctar

Anti-Venom, Horrifying Healer

Agatha's Soul Cauldron

Branching Evolution

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 Branching Evolution.
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 loop turns a clever alchemy of damage prevention and counter-doubling into absolute destruction by combining Agatha's Soul Cauldron with the key creature cards exiled within it. By exiling Deathbringer Thoctar to Agatha's Soul Cauldron, its activated ability is granted to Anti-Venom, Horrifying Healer, allowing Anti-Venom to shoot itself for 1 damage; thanks to Anti-Venom's own damage-prevention replacement effect and the counter-doubling power of Branching Evolution, that self-inflicted damage generates a surplus of +1/+1 counters to fuel the cycle infinitely.