Otherworldly Escort + Amoeboid Changeling + Thornbite Staff + Bloodflow Connoisseur

Otherworldly Escort

Amoeboid Changeling

Thornbite Staff

Bloodflow Connoisseur

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 Bloodflow Connoisseur 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 Bloodflow Connoisseur ability.
7. Repeat.