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

Anti-Venom, Horrifying Healer

Agatha's Soul Cauldron

Triskelion

Doubling Season

How it works

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

This loop relies on Agatha's Soul Cauldron to grant Triskelion's activated ability to Anti-Venom, Horrifying Healer, turning the healer into a lethal artillery piece. Because Doubling Season doubles any counters placed on a permanent, every time Anti-Venom's damage-prevention replacement effect triggers, it nets a surplus of +1/+1 counters rather than just breaking even. You can then use those extra counters to continuously ping your opponents or their creatures for infinite damage.