Anti-Venom, Horrifying Healer + Agatha's Soul Cauldron + Pir, Imaginative Rascal + Walking Ballista

Anti-Venom, Horrifying Healer

Agatha's Soul Cauldron

Pir, Imaginative Rascal

Walking Ballista

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 Pir.
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.

By exiling Walking Ballista into Agatha's Soul Cauldron, its deadly activated abilities are granted to any creature you control that bears a +1/+1 counter. Anti-Venom, Horrifying Healer happily takes on those abilities while utilizing its own passive replacement effect to convert self-inflicted damage into prevention and growth. Meanwhile, Pir, Imaginative Rascal acts as the ultimate amplifier, increasing every counter gained so that the loop not only sustains itself, but grows exponentially.