Mikaeus, the Unhallowed + Goblin Bombardment + Glen Elendra Archmage

Mikaeus, the Unhallowed

Goblin Bombardment

Glen Elendra Archmage

How it works

1. Activate Goblin Bombardment 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 Goblin Bombardment ability.
4. Activate Goblin Bombardment 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 Goblin Bombardment ability.
7. Repeat.