Myr Welder, Umbral Mantle, and Sisay's Ring

Prerequisites

• Myr Welder on the battlefield
• Umbral Mantle on the battlefield
• Sisay's Ring in exile

Steps

1. Activate Myr Welder using Sisay's Ring's ability by tapping it, adding at least
2. Activate Umbral Mantle by paying , untapping Myr Welder
3. Repeat

Results

• Infinite untap of creatures you control
• Infinite mana creatures you control can produce
• Infinitely large creature until end of turn
• Infinite colorless mana