Koh, the Face Stealer, and Bloodthirster

Prerequisites

• Koh, the Face Stealer on the battlefield
• Bloodthirster in exile

Steps

1. Activate Koh by paying 1 life, causing it to gain Bloodthirster's triggered and activated abilities
2. Deal combat damage using Koh, triggering Koh, causing you to untap it and to get an additional combat phase after this one
3. Repeat step 2 each combat phase

Results

• Infinite combat phases
• Infinite combat damage