Tainted Observer, Animation Module, Crystalline Crawler, Hardened Scales, and Tekuthal, Inquiry Dominus

Prerequisites

• Tainted Observer on the battlefield
• Animation Module on the battlefield
• Crystalline Crawler on the battlefield
• Hardened Scales on the battlefield
• Tekuthal, Inquiry Dominus on the battlefield
• Crystalline Crawler has at least one +1/+1 counter
• You have a way to put a +1/+1 counter on a creature you control
• available

Steps

1. Put a +1/+1 counter on a creature you control
2. Animation Module triggers, causing you to pay to create a 1/1 Servo artifact creature token
3. The Servo enters the battlefield, triggering Tainted Observer, causing you to pay 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
7. Resolve the final Animation Module trigger, causing you to pay to create a 1/1 Servo artifact creature token
8. Repeat from step 3

Results

• Infinite +1/+1 counters on Crystalline Crawler
• Infinite colored mana
• Infinite creature tokens
• Infinite ETB
• Infinite proliferate