Optimus Prime, Hero // Optimus Prime, Autobot Leader + Mikaeus, the Unhallowed + Yahenni, Undying Partisan

Optimus Prime, Hero // Optimus Prime, Autobot Leader

Mikaeus, the Unhallowed

Yahenni, Undying Partisan

How it works

1. Activate Yahenni by sacrificing Optimus Prime, Hero.
2. When Optimus Prime, Hero dies, its second ability triggers, returning it from your graveyard to the battlefield as Optimus Prime, Autobot Leader.
3. Activate Yahenni by sacrificing Optimus Prime, Autobot Leader.
4. When Optimus Prime, Autobot Leader dies, Mikaeus triggers, returning Optimus Prime from your graveyard to the battlefield as Optimus Prime, Hero with a +1/+1 counter on it.
5. Resolve both Yahenni abilities from steps 1 and 3.
6. Repeat.

This clever loop relies on the constant transformation and resurrection of Optimus Prime, Hero / Optimus Prime, Autobot Leader to continuously cycle between its two faces. Mikaeus, the Unhallowed provides the crucial lord effect and grants undying to non-Human creatures, allowing the Autobot Leader side to return with a +1/+1 counter whenever it dies, while Optimus's own printed death trigger brings it back as the Hero whenever that side hits the graveyard. By using Yahenni, Undying Partisan as a free sacrifice outlet to feed this alternating cycle, you achieve an endless loop of leaves-the-battlefield, enters-the-battlefield, and death triggers.