Mikaeus, the Unhallowed + Ashnod's Altar + Glen Elendra Archmage

Mikaeus, the Unhallowed

Ashnod's Altar

Glen Elendra Archmage

How it works

1. Activate Ashnod's Altar 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. Activate Ashnod's Altar by sacrificing Glen Elendra Archmage.
4. When Glen Elendra Archmage dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
5. Repeat.

This loop is a masterclass in counter cancellation, using Mikaeus, the Unhallowed to keep Glen Elendra Archmage looping endlessly through your graveyard. Whenever you sacrifice the Archmage to Ashnod's Altar, its native persist ability brings it back with a -1/-1 counter, but Mikaeus grants it undying so the next death returns it with a +1/+1 counter instead; when these two opposing counters meet on the Archmage, state-based actions cause them to annihilate each other, resetting its mortality. This allows you to sacrifice the Archmage repeatedly for an endless supply of colorless mana while its repeatable, counter-equipped negation engine locks opponents out of ever resolving a noncreature spell.