Otherworldly Escort + Amoeboid Changeling + Intruder Alarm + Umbral Collar Zealot

Otherworldly Escort

Amoeboid Changeling

Intruder Alarm

Umbral Collar Zealot

How it works

1. Activate Amoeboid Changeling's second ability by tapping it, causing Otherworldly Escort to lose all creature types until end of turn.
2. Activate Umbral Collar Zealot by sacrificing Otherworldly Escort.
3. When Otherworldly Escort dies, it triggers, returning itself from your graveyard to the battlefield as a Spirit Detective.
4. When Otherworldly Escort enters, Intruder Alarm triggers, untapping all creatures.
5. Resolve the Umbral Collar Zealot ability.
6. Repeat.

By stripping Otherworldly Escort of its native creature types using Amoeboid Changeling's second ability, you bypass its safeguard against returning as a Spirit—meaning every time Umbral Collar Zealot sacrifices it, it happily resurrects itself with four new charge counters. Each resurrection triggers Intruder Alarm, which conveniently untaps your entire board so you can repeat the loop endlessly. The result is a perpetual motion machine of sacrifices, enter-the-battlefield effects, and surveils that turns your creatures into an untap engine while your opponents look on in utter bewilderment.