Survey Mechan + Mortuary + Ashnod's Altar + Insidious Roots + Chatterfang, Squirrel General

Survey Mechan

Mortuary

Ashnod's Altar

Insidious Roots

Chatterfang, Squirrel General

How it works

1. Activate Survey Mechan by sacrificing it.
2. When Survey Mechan dies, Mortuary triggers, putting Survey Mechan from your graveyard onto the top of your library.
3. Insidious Roots triggers, creating two creature tokens and putting a +1/+1 counter on each Plant you control.
4. Resolve the Survey Mechan ability, dealing 3 damage to any target and causing you to draw three cards and gain 3 life.
5. Activate Ashnod's Altar twice by sacrificing the two creature tokens, adding CCCC.
6. Cast Survey Mechan by paying 4.
7. Repeat.

This loop turns the heavy mana cost of Survey Mechan into a self-sustaining cycle by using Ashnod's Altar to harvest the tokens generated along the way. Whenever Survey Mechan hits the graveyard, Mortuary intercepts it to place it right back on top of your library, and Insidious Roots capitalized on that creature card leaving the graveyard by spawning a Plant token. Chatterfang, Squirrel General doubles down on that token creation by bringing a Squirrel along for the ride, meaning every iteration yields two sacrifices for Ashnod's Altar to fuel the next casting of Survey Mechan while ticking Insidious Roots's counters higher and higher.