Time Sieve, Encroaching Mycosynth, Rionya, Fire Dancer, and Underworld Hermit

Prerequisites

• Time Sieve on the battlefield
• Encroaching Mycosynth on the battlefield
• Rionya, Fire Dancer on the battlefield
• Underworld Hermit on the battlefield

Steps

1. At the beginning of your combat phase, Rionya triggers, creating at least one token copy of Underworld Hermit with haste
2. When the Underworld Hermit token enters the battlefield, it triggers, creating at least four 1/1 Squirrel creature tokens
3. Activate Time Sieve by tapping it, sacrificing the Underworld Hermit token and the Squirrel tokens, causing you to take an extra turn after this one
4. Repeat each turn

Results

• Infinite turns