Strength of Will, Walking Ballista, and Lae'zel, Vlaakith's Champion

Prerequisites

• Strength of Will in hand
• Walking Ballista on the battlefield
• Lae'zel, Vlaakith's Champion on the battlefield
• available

Steps

1. Cast Strength of Will by paying , targeting Walking Ballista
2. Activate Walking Ballista by removing a +1/+1 counter from it, dealing 1 damage to it
3. Walking Ballista triggers, putting two +1/+1 counters on it due to Lae'zel
4. Activate Walking Ballista by removing a +1/+1 counter from it, dealing 1 damage to any target
5. Repeat from step 2

Results

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