Mastermind

Mastermind is a Magic Arena-specific format for Magic: The Gathering. The format is not an on-demand format, instead being one exclusive to events.

Description
In this format, players are given a large Singleton deck (180+ cards) and the ability "Discard a card: create a Utopia land token with "undefined: Add one mana of any color". Activate this ability once per turn and only at any time you could cast a sorcery", reminiscent of the Mental Magic land rule. The deck has no lands and is largely color balanced, leaving it up to the players as to how to approach playing out their hand. The decklist varies from event to event.