Iron Spider, Stark Upgrade, Voltaic Construct, Crystalline Crawler, and Workhorse

Prerequisites

• Iron Spider, Stark Upgrade on the battlefield
• Voltaic Construct on the battlefield
• Crystalline Crawler on the battlefield
• Workhorse on the battlefield

Steps

1. Activate Iron Spider by tapping it, putting a +1/+1 counter on each artifact creature and/or Vehicle you control
2. Activate Workhorse and Crystalline Crawler by removing a +1/+1 counter from each of them, adding
3. Activate Voltaic Construct by paying , untapping Iron Spider
4. Repeat

Results

• Infinite +1/+1 counters on artifact creatures you control