Survey Mechan + Mortuary + Ashnod's Altar + Chalk Outline + Primal Vigor

Survey Mechan

Mortuary

Ashnod's Altar

Chalk Outline

Primal Vigor

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. Chalk Outline triggers, creating two creature tokens and two Clue tokens
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 clever loop centers around sacrificing Survey Mechan to fuel its own massive ability, while Mortuary steps in to bypass the graveyard and tuck it right back onto the top of your library. From there, drawing cards naturally lets you recast it, but the true engine of this combo is fueled by Chalk Outline: every time Survey Mechan leaves your graveyard, it spawns Detective tokens and Clue tokens. Because Primal Vigor doubles all of those incoming tokens, you get an absolute surplus of artifacts and creatures to feed directly into Ashnod's Altar, generating more than enough colorless mana to cast Survey Mechan again and repeat the entire cycle indefinitely.