Ulasht, the Hate Seed + Agatha's Soul Cauldron + Wildwood Mentor + Ashnod's Altar

Ulasht, the Hate Seed

Agatha's Soul Cauldron

Wildwood Mentor

Ashnod's Altar

How it works

1. Activate Wildwood Mentor using Ulasht's ability by paying 1 and removing a +1/+1 counter from it, creating a 1/1 Saproling creature token.
2. When the Saproling enters the battlefield, Wildwood Mentor's first ability triggers, putting a +1/+1 counter on itself.
3. Activate Ashnod's Altar by sacrificing the Saproling, adding CC.
4. Repeat.
5. Once you have infinite mana, you may forego sacrificing the Saprolings.

This ingenious loop centers around Agatha's Soul Cauldron, which allows Ulasht, the Hate Seed to inherit activated abilities from creature cards exiled within it—specifically granting Ulasht the ability to convert a +1/+1 counter and one mana into a brand-new Saproling token. With Ashnod's Altar standing ready to sacrifice those newly minted tokens for a tidy profit of two colorless mana, you generate an immediate surplus to fuel the loop. Meanwhile, Wildwood Mentor steps in as the crucial growth engine, triggering whenever a token enters the battlefield to replenish Ulasht's dwindling counters and keep the mana-producing engine humming infinitely.