Tainted Observer + Animation Module + Crystalline Crawler + Primal Vigor + Tekuthal, Inquiry Dominus

Tainted Observer

Animation Module

Crystalline Crawler

Primal Vigor

Tekuthal, Inquiry Dominus

How it works

1. Put a +1/+1 counter on a creature you control.
2. Animation Module triggers, causing you to pay 1 to create a 1/1 Servo artifact creature token.
3. The Servo enters the battlefield, triggering Tainted Observer, causing you to pay 2 to put four +1/+1 counters on Crystalline Crawler.
4. Animation Module triggers four times.
5. Resolve the first three Animation Module triggers, choosing not to pay.
6. Activate Crystalline Crawler's first ability three times by removing three +1/+1 counters from it, adding 3.
7. Resolve the final Animation Module trigger, causing you to pay 1 to create a 1/1 Servo artifact creature token.
8. Repeat from step 3.

This intricate loop turns a single +1/+1 counter into an overwhelming cascade of resources by feeding the mechanical synergy between your permanents. Every time a Servo enters the battlefield, Tainted Observer triggers to proliferate, an effect doubled by Tekuthal, Inquiry Dominus to add multiple counters at once—a multiplication further supercharged by Primal Vigor. This flood of counters allows Animation Module to continuously mint new tokens, while Crystalline Crawler acts as both your mana source and counter storage, letting you peel off +1/+1 counters for mana and continuously replenish them to keep the engine running infinitely.