Mendicant Core, Guidelight, Urza, Lord High Artificer, and Worldwalker Helm

Prerequisites

• Mendicant Core, Guidelight on the battlefield
• Urza, Lord High Artificer on the battlefield
• Worldwalker Helm in hand
• You have max speed
• available

Steps

1. Cast Worldwalker Helm by paying
2. Mendicant Core triggers, causing you to pay to copy the Worldwalker Helm spell
3. Resolve both Worldwalker Helm spells
4. Activate Urza by tapping a Worldwalker Helm, adding
5. Activate a Worldwalker Helm by paying and tapping it, creating a token copy of the Worldwalker Helm token plus an additional Map token for each Worldwalker Helm you control
6. Activate Urza twice by tapping two Worldwalker Helm tokens, adding
7. Repeat from step 5

Results

• Infinite blue mana
• Exile your library
• Cast all cards in your library without paying their mana costs
• Infinite Map tokens
• Infinite Worldwalker Helm tokens