Anti-Venom, Horrifying Healer + Agatha's Soul Cauldron + Branching Evolution + Walking Ballista

Prerequisites

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Steps

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

Effects

• Infinite +1/+1 counters on a creature
• Infinite damage