Time Sieve, Encroaching Mycosynth, Delina, Wild Mage, and Underworld Hermit

Prerequisites

• Time Sieve on the battlefield
• Encroaching Mycosynth on the battlefield
• Delina, Wild Mage on the battlefield
• Underworld Hermit on the battlefield
• Delina does not have summoning sickness and cannot be blocked and killed by an opponent

Steps

1. Declare Delina as an attacker
2. Delina triggers, creating at least one token copy of Underworld Hermit with haste
3. When the Underworld Hermit token enters the battlefield, it triggers, creating at least four 1/1 Squirrel creature tokens
4. 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
5. Repeat each turn

Results

• Infinite turns