Urza, Prince of Kroog, Corridor Monitor, and Metalworker

Prerequisites

• Urza, Prince of Kroog on the battlefield
• Corridor Monitor on the battlefield
• Metalworker on the battlefield
• You have at least three artifact cards in hand
• Metalworker does not have summoning sickness

Steps

1. Activate Metalworker by tapping it and revealing at least three artifact cards from your hand, adding at least six
2. Activate Urza by paying , creating a token copy of Corridor Monitor that is a 1/1 Soldier in addition to its other types
3. When the Corridor Monitor token enters the battlefield, it triggers, untapping Metalworker
4. Repeat
5. If you have four or more artifact cards in hand, this combo nets infinite colorless mana, and you may target any other artifact(s) you control

Results

• Infinite colorless mana
• Infinite creature copies of artifacts you control
• Infinite creature tokens
• Infinite ETB