Urza, Prince of Kroog + Turnabout + Mycosynth Lattice + Mnemonic Wall

Urza, Prince of Kroog

Turnabout

Mycosynth Lattice

Mnemonic Wall

How it works

1. Activate all mana-producing lands you control by tapping them, adding at least 10.
2. Cast Turnabout by paying 4, untapping all lands you control.
3. Activate Urza by paying 6, creating a token copy of Mnemonic Wall that is a 1/1 Soldier in addition to its other types.
4. When the Mnemonic Wall token enters the battlefield, it triggers, returning Turnabout to your hand from your graveyard.
5. Repeat.
6. If lands you control can tap to proudce at least 11, this combo nets infinite mana, which can be used to activate Urza's ability infinitely and/or cast Turnabout choosing its other modes.

This loop achieves infinite power by turning the battlefield into a machine that perpetually rebuilds and reuses its own fuel. Mycosynth Lattice is the grand enabler here, turning Mnemonic Wall and every land you control into an artifact so they can interact seamlessly with the rest of the engine. Once your lands are producing enough mana, Turnabout untaps them to keep the cycle going, while Urza, Prince of Kroog spends a portion of that mana to mint fresh token copies of Mnemonic Wall. Every time a Mnemonic Wall token enters, its triggered ability plucks Turnabout right back out of your graveyard, setting you up to cast it again and repeat the process for limitless mana, storm, and artifact creature tokens.