Basalt Monolith, Living Brain, Mechanical Marvel, and Biomancer's Familiar

Prerequisites

• Basalt Monolith on the battlefield
• Living Brain, Mechanical Marvel on the battlefield
• Biomancer's Familiar on the battlefield

Steps

1. Cause Basalt Monolith to become a creature using Living Brain
2. Activate Basalt Monolith's first ability by tapping it, adding
3. Activate Basalt Monolith's last ability by paying , untapping it
4. Repeat from step 2

Results

• Infinite colorless mana