Underworld Breach, Lion's Eye Diamond, and Ambassador Laquatus

Prerequisites

• Underworld Breach on the battlefield
• Lion's Eye Diamond on the battlefield
• Ambassador Laquatus on the battlefield

Steps

1. Sacrifice Lion's Eye Diamond producing
2. Activate Ambassador Laquatus's ability for 3 milling 3 cards
3. Cast Lion's Eye Diamond for its escape cost with Underworld Breach, exiling the 3 cards milled by Laquatus
4. Repeat the cycle until you've milled yourself out

Results

• Mill your entire library