Optimus Prime, Hero // Optimus Prime, Autobot Leader + Mikaeus, the Unhallowed + Grimgrin, Corpse-Born

Optimus Prime, Hero // Optimus Prime, Autobot Leader

Mikaeus, the Unhallowed

Grimgrin, Corpse-Born

How it works

1. Activate Grimgrin 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 Grimgrin 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 Grimgrin abilities from steps 1 and 3, putting two +1/+1 counters on it.
6. Repeat.