The Great Goblin, The Red Terror, and Conspiracy

Prerequisites

• The Great Goblin on the battlefield
• The Red Terror on the battlefield
• Conspiracy on the battlefield

Steps

1. Put a counter on The Red Terror
2. The Great Goblin's first ability triggers, as The Red Terror is a Goblin, Orc or Army due to Conspiracy, dealing 2 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