Otherworldly Escort + Amoeboid Changeling + Thornbite Staff + Altar of Dementia

Otherworldly Escort

Amoeboid Changeling

Thornbite Staff

Altar of Dementia

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 Altar of Dementia by sacrificing Otherworldly Escort.
3. When Otherworldly Escort dies, it and Amoeboid Changeling trigger.
4. Resolve the Amoeboid Changeling trigger, untapping it.
5. Resolve the Otherworldly Escort trigger, returning itself from your graveyard to the battlefield as a Spirit Detective.
6. Resolve the Altar of Dementia ability.
7. Repeat.

This cunning loop uses Amoeboid Changeling to strip away Otherworldly Escort's native creature types, neatly bypassing its "if it's not a Spirit" restriction so that it can return to the battlefield whenever it dies. Once Altar of Dementia sends the Escort to the graveyard, its resurrection trigger fires off reliably over and over again. While Thornbite Staff isn't strictly required for this specific mill-and-sacrifice engine to loop, changeling shenanigans like this often leverage tribal synergies and untap tools to keep the board state entirely under your control.