Tarrian's Soulcleaver + Scurry Oak + Umbral Collar Zealot

Tarrian's Soulcleaver

Scurry Oak

Umbral Collar Zealot

How it works

1. Put a +1/+1 counter on Scurry Oak.
2. Scurry Oak triggers, creating a 1/1 Squirrel creature token.
3. Activate Umbral Collar Zealot by sacrificing the Squirrel.
4. When the Squirrel dies, Tarrian's Soulcleaver triggers, putting a +1/+1 counter on Scurry Oak.
5. Scurry Oak triggers, creating a 1/1 Squirrel creature token.
6. Resolve the Umbral Collar Zealot ability, putting a +1/+1 counter on it.
7. Repeat from step 3.

This loop relies on a clever perpetuum mobile between Scurry Oak and Tarrian's Soulcleaver, where any initial +1/+1 counter on the Oak sets off a chain reaction of token generation and growth. By using Umbral Collar Zealot to sacrifice the newly minted Squirrel token, you send an artifact creature straight to the graveyard, triggering the Soulcleaver to place a fresh +1/+1 counter back onto Scurry Oak. This instantly restarts the Oak's ability to breed another Squirrel, fueling an endless cycle of sacrifices, deaths, and surveil actions.