Myr Welder, Encroaching Mycosynth, Empowered Autogenerator, and Duergar Mine-Captain

Prerequisites

• Myr Welder on the battlefield
• Encroaching Mycosynth on the battlefield
• Empowered Autogenerator in exile
• Duergar Mine-Captain in exile
• Myr Welder does not have summoning sickness
• (at most) available

Steps

1. Activate Myr Welder using Empowered Autogenerator's ability by tapping it, putting a charge counter on Myr Welder and adding or for each charge counter on Myr Welder
2. Activate Myr Welder using Duergar Mine-Captain's ability by paying and untapping it, giving attacking creatures +1/+0 until end of turn
3. Repeat

Results

• Infinite charge counters on Myr Welder
• Infinite colored mana
• Infinitely powerful attacking creatures until end of turn