Mikaeus, the Unhallowed + Thermopod + Putrid Goblin

Mikaeus, the Unhallowed

Thermopod

Putrid Goblin

How it works

1. Activate Thermopod by sacrificing Putrid Goblin.
2. When Putrid Goblin dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Activate Thermopod by sacrificing Putrid Goblin.
4. When Putrid Goblin dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
5. Repeat.

This clever loop exploits a persistent tug-of-war between two opposing counter mechanics. Putrid Goblin naturally relies on its persist ability to return from the graveyard with a -1/-1 counter, but when Mikaeus, the Unhallowed grants it undying, the subsequent death triggers alternate between the two abilities; because the +1/+1 counter from undying and the -1/-1 counter from persist instantly annihilate each other upon entering the battlefield as a state-based action, the Goblin never accumulates counters to shut the loop down. Thermopod capitalizes on this endless resurrection cycle by turning each sacrifice directly into red mana, fueling a perpetual engine that generates infinite death triggers, sacrifice triggers, and mana to end the game.