Mikaeus, the Unhallowed + Woodfall Primus + Ashnod's Altar

Mikaeus, the Unhallowed

Woodfall Primus

Ashnod's Altar

How it works

1. Activate Ashnod's Altar by sacrificing Woodfall Primus.
2. When Woodfall Primus dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. When Woodfall Primus enters, it triggers, destroying a noncreature permanent.
4. Activate Ashnod's Altar by sacrificing Woodfall Primus.
5. When Woodfall Primus dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
6. When Woodfall Primus enters, it triggers, destroying a noncreature permanent.
7. Repeat.

This vicious loop relies on a brilliant counter-cancellation trick: when Woodfall Primus enters the battlefield, its persist ability normally brings it back with a -1/-1 counter, but Mikaeus, the Unhallowed grants it undying so it returns with a +1/+1 counter instead whenever it dies with a counter already present. Because these two opposing counters annihilate each other state-based-wise upon entry, the giant tree can bounce back and forth between life and death indefinitely. Meanwhile, Ashnod's Altar readily turns each sacrifice into a steady stream of colorless mana while ensuring Woodfall Primus triggers its noncreature permanent destruction over and over again until your opponents are completely stripped of their artifacts, enchantments, and lands.