Marvin, Murderous Mimic, Argothian Elder, and Simic Ragworm

Prerequisites

• Marvin, Murderous Mimic on the battlefield
• Argothian Elder on the battlefield
• Simic Ragworm on the battlefield

Steps

1. Activate Marvin using Argothian Elder's ability by tapping it, untapping two lands you control
2. Activate the two lands by tapping them, adding at least
3. Activate Marvin using Simic Ragworm's ability by paying , untapping it
4. Repeat

Results

• Infinite mana lands you control can produce
• Infinite untap of lands you control