Mikaeus, the Unhallowed + Umbral Collar Zealot + Glen Elendra Archmage

Mikaeus, the Unhallowed

Umbral Collar Zealot

Glen Elendra Archmage

How it works

1. Activate Umbral Collar Zealot by sacrificing Glen Elendra Archmage.
2. When Glen Elendra Archmage dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Resolve the Umbral Collar Zealot ability.
4. Activate Umbral Collar Zealot by sacrificing Glen Elendra Archmage.
5. When Glen Elendra Archmage dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
6. Resolve the Umbral Collar Zealot ability.
7. Repeat.