Red Hulk, Grand Crescendo, and Boros Reckoner

Prerequisites

• Red Hulk on the battlefield
• Grand Crescendo in hand
• Boros Reckoner on the battlefield
• available

Steps

1. Give Red Hulk and Boros Reckoner indestructible using Grand Crescendo
2. Deal damage to Red Hulk
3. Red Hulk triggers, putting a +1/+1 counter on it and dealing damage to Boros Reckoner
4. Boros Reckoner triggers, dealing damage to Red Hulk
5. Repeat from step 3

Results

• Infinite +1/+1 counters on a creature
• Infinite damage to one opponent