Ashaya, Soul of the Wild + Celestial Dawn + Emeria Shepherd + Umbral Collar Zealot

Ashaya, Soul of the Wild

Celestial Dawn

Emeria Shepherd

Umbral Collar Zealot

How it works

1. Cast any creature by paying its mana cost.
2. When the creature enters as a Plains due to Ashaya and Emeria Shepherd, Emeria Shepherd triggers.
3. Holding priority, activate Umbral Collar Zealot by sacrificing the creature cast in step 1.
4. Resolve the Emeria Shepherd trigger, returning another creature from your graveyard to the battlefield.
5. Repeat from step 2.

This clever engine turns every creature you cast into a perpetual motion machine by weaving together their type-changing rules. As long as Celestial Dawn is on the field, your lands become Plains, which cascades over to make Ashaya, Soul of the Wild's ability turn every nontoken creature you control into a Forest land in addition to its other types. Because of this, casting any new creature immediately triggers Emeria Shepherd's landfall ability for a Plains, letting you set up a loop where you sacrifice that creature to Umbral Collar Zealot's surveil ability before the Shepherd trigger resolves. This immediately feeds the graveyard with targets for Emeria Shepherd to yank straight back to the battlefield, endlessly recycling your threats while generating infinite sacrifices, leaves-the-battlefield, and death triggers.