Ultron, Artificial Malevolence, Voltaic Construct, and Mana Vault

Prerequisites

• Ultron, Artificial Malevolence on the battlefield
• Voltaic Construct on the battlefield
• Mana Vault in hand
• available

Steps

1. Cast Mana Vault by paying its mana cost
2. When Mana Vault enters, Ultron triggers
3. Holding priority, activate Mana Vault by tapping it, adding Resolve the Ultron trigger, causing you to pay to create a copy of Mana Vault that is a 2/2 Robot Villain creature
4. During your next turn, activate the Mana Vault token by tapping it, adding Activate Voltaic Construct by paying , untapping the Mana Vault token
5. Repeat from step 5

Results

• Infinite colorless mana