Thermopod + Furystoke Giant + Hardened Academic

Thermopod

Furystoke Giant

Hardened Academic

How it works

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

This brilliant loop relies on Thermopod to sacrifice Furystoke Giant for red mana, which simultaneously triggers the Giant's persist ability to return it from the graveyard with a -1/-1 counter. Because a card leaving the graveyard triggers Hardened Academic, you can place a +1/+1 counter onto the returning Furystoke Giant, effectively neutralizing the persist counter through the rule of state-based counter annihilation. Repeating this cycle feeds an endless engine of creature sacrifices, leaving you with infinite red mana and all the death and entry triggers you could ever desire.