Basalt Monolith, Tough Cookie, and Agatha of the Vile Cauldron

Prerequisites

• Basalt Monolith on the battlefield
• Tough Cookie on the battlefield
• Agatha of the Vile Cauldron on the battlefield
• Basalt Monolith does not have summoning sickness
• Agatha of the Vile Cauldron has power 1 or greater
• at most available

Steps

1. Activate Tough Cookie's first ability by paying at most , causing Basalt Monolith to become a 4/4 artifact creature until end of turn
2. Activate Basalt Monolith's first ability by tapping it, adding
3. activate Basalt Monolith's second ability by paying at most , untapping it
4. Repeat from step 2

Results

• Infinite colorless mana