Casey Jones, Back Alley Brute, and The Red Terror

Prerequisites

• Casey Jones, Back Alley Brute on the battlefield
• The Red Terror on the battlefield

Steps

1. Declare Casey as an attacker, triggering its first ability, putting a +1/+1 counter on it
2. Casey's second ability triggers, dealing 1 damage to an opponent
3. The Red Terror triggers, putting a +1/+1 counter on it
4. Repeat from step 2

Results

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