Cass, Hand of Vengeance + Griffin Guide + Spawning Pit

Cass, Hand of Vengeance

Griffin Guide

Spawning Pit

How it works

1. Activate Spawning Pit by sacrificing the creature with Griffin Guide attached.
2. When the creature dies, Cass and Griffin Guide trigger.
3. Resolve the Griffin Guide trigger, creating a 2/2 Griffin creature token.
4. Resolve the Cass trigger, returning Griffin Guide from your graveyard to the battlefield attached to another creature you control.
5. Resolve the Spawning Pit ability
6. Repeat.