Anti-Venom, Horrifying Healer + Agatha's Soul Cauldron + Walking Ballista + Doubling Season

Anti-Venom, Horrifying Healer

Agatha's Soul Cauldron

Walking Ballista

Doubling Season

How it works

1. Activate Anti-Venom using Walking Ballista'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 Doubling Season.
2. Activate Anti-Venom using Walking Ballista's ability by removing a +1/+1 counter from it, dealing 1 damage to any target.
3. Repeat.

This clever loop transforms Anti-Venom, Horrifying Healer into a lethal engine by using Agatha's Soul Cauldron to grant Walking Ballista's activated abilities to everything with a counter. Thanks to Doubling Season doubling any counters placed on a permanent, every time Anti-Venom deals damage to itself, its own replacement effect generates a net surplus of +1/+1 counters. You can then endlessly channel Walking Ballista's counter-removal to deal infinite damage to any target while recycling your counters to keep the loop going indefinitely.