Time Sieve, and Exsanguinator Cavalry

Prerequisites

• Time Sieve on the battlefield
• Exsanguinator Cavalry on the battlefield
• You control at least five Knights that do not have summoning sickness and that cannot be blocked by an opponent

Steps

1. Deal combat damage using at least five Knights
2. Exsanguinator Cavalry triggers, putting a +1/+1 counter on each attacking Knight and creating that many Blood artifact tokens
3. Activate Time Sieve by tapping it and sacrificing five Bloods, causing you to take an extra turn after this one
4. Repeat

Results

• Infinite turns