Mikaeus, the Unhallowed + Thermopod + Soulstinger

Mikaeus, the Unhallowed

Thermopod

Soulstinger

How it works

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

This loop is a masterclass in counter-cancellation, turning Thermopod into an infinite red mana engine fueled by life and death alike. When you sacrifice Soulstinger to the Thermopod, Mikaeus, the Unhallowed grants the insect undying, bringing it right back to the battlefield with a +1/+1 counter. That's where Soulstinger's own entering-the-battlefield ability shines, dropping two -1/-1 counters onto itself; state-based actions immediately cause the +1/+1 counter and one -1/-1 counter to annihilate each other, leaving Soulstinger with no +1/+1 counters and primed to die and repeat the cycle endlessly.