Time Sieve + Encroaching Mycosynth + Kiki-Jiki, Mirror Breaker + Underworld Hermit

Time Sieve

Encroaching Mycosynth

Kiki-Jiki, Mirror Breaker

Underworld Hermit

How it works

1. Activate Kiki-Jiki by tapping it, creating a 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.

This ingenious loop turns a modest swarm of rodents into an endless chain of chronological breakthroughs, fueled entirely by the subtle rule-bending of Encroaching Mycosynth. Because that enchantment turns all your nonland permanents into artifacts, the Squirrel tokens and creatures you generate instantly qualify as the sacrificial fuel required by Time Sieve. You simply use Kiki-Jiki, Mirror Breaker to continually copy Underworld Hermit, whose own entry triggers yield a fresh crop of devotion-backed tokens on every single turn. Sacrifice the newly minted Underworld Hermit token along with its litter of Squirrels to Time Sieve, take your extra turn, and repeat the process to lock down the game forever.