Voltaic Construct, The Blackstaff of Waterdeep, and Basalt Monolith

Prerequisites

• Voltaic Construct on the battlefield
• The Blackstaff of Waterdeep on the battlefield
• Basalt Monolith on the battlefield
• Basalt Monolith does not have summoning sickness
• available

Steps

1. Activate Basalt Monolith's first ability by tapping it, adding
2. Activate The Blackstaff of Waterdeep by paying and tapping it, causing Basalt Monolith to become an artifact creature until end of turn
3. Activate Voltaic Construct by paying , untapping Basalt Monolith
4. Activate Basalt Monolith's first ability by tapping it, adding
5. Repeat from step 3

Results

• Infinite colorless mana
• Infinite untap of artifact creatures you control