Anti-Venom, Horrifying Healer + Agatha's Soul Cauldron + Walking Ballista + Benevolent Hydra

Anti-Venom, Horrifying Healer

Agatha's Soul Cauldron

Walking Ballista

Benevolent Hydra

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 Benevolent Hydra.
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 engine uses Agatha's Soul Cauldron to grant Anti-Venom, Horrifying Healer the activated abilities of Walking Ballista, turning any existing +1/+1 counters into direct damage. Every time Walking Ballista's counter-removal ability is used to make Anti-Venom deal damage to itself, Anti-Venom's replacement effect prevents that damage and places those +1/+1 counters back on itself instead. Benevolent Hydra amplifies this growth by adding an extra counter on top of every placement, allowing the loop to easily generate infinite +1/+1 counters while machine-gunning down any target for infinite damage.