Kinnan, Bonder Prodigy, Grim Monolith, and Spark Double

Prerequisites

• Kinnan, Bonder Prodigy on the battlefield
• Grim Monolith on the battlefield
• Spark Double on the battlefield
• Spark Double is a copy of Kinnan

Steps

1. Activate Grim Monolith's first ability by tapping it, adding
2. Activate Grim Monolith's last ability by paying , untapping it
3. Repeat

Results

• Infinite colorless mana