Captain America, Team Leader + Animation Module + Arcane Adaptation + Phyrexian Altar

Captain America, Team Leader

Animation Module

Arcane Adaptation

Phyrexian Altar

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. When the Servo enters as a Hero due to Arcane Adaptation, Captain America triggers, putting a +1/+1 counter on it and the Servo.
4. Animation Module triggers twice.
5. Holding priority, activate Phyrexian Altar by sacrificing the Servo, adding 1.
6. Resolve the first Animation Module trigger, choosing not to pay.
7. Resolve the second Animation Module trigger, causing you to pay 1 to create a 1/1 Servo artifact creature token.
8. Repeat from step 3.

This loop transforms a simple counter placement into an endless mechanical engine by leveraging the type-changing magic of Arcane Adaptation to turn every token you make into a Hero. Because every creature you control becomes a Hero, each Servo generated triggers Captain America, Team Leader to place fresh +1/+1 counters on both itself and Captain America. Those new counters immediately trigger Animation Module, giving you the chance to pay a single mana to spawn another Servo. You can then feed that newly minted Servo into Phyrexian Altar to generate the exact mana needed to pay Animation Module's fee, sustaining the entire loop indefinitely.