Requires

Ulasht, the Hate Seed must be in exile (exiled by Agatha's Soul Cauldron). Agatha's Soul Cauldron must be on the battlefield. Wildwood Mentor must be on the battlefield. Ashnod's Altar must be on the battlefield. Wildwood Mentor has at least one +1/+1 counter on it. Mana needed:

Steps

1. Activate Wildwood Mentor using Ulasht's ability by paying 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 .
4. Repeat.
5. Once you have infinite mana, you may forego sacrificing the Saprolings.

Results