Basalt Monolith, Mishra, Eminent One, and Heartstone

Prerequisites

• Basalt Monolith on the battlefield
• Mishra, Eminent One on the battlefield
• Heartstone on the battlefield

Steps

1. At the beginning of your combat phase, Mishra triggers, creating a token copy of Basalt Monolith that is a 4/4 Construct with haste named Mishra's Warform
2. Activate Mishra's Warform's first ability by tapping it, adding
3. Activate Mishra's Warform's last ability by paying , untapping it
4. Repeat from step 2

Results

• Infinite colorless mana