Mox Ruby

A zero-cost artifact that enters and immediately produces a colored source is, in design terms, a spell that costs nothing and keeps paying you: no card disadvantage, no mana to recoup, just an extra red mana from the moment it resolves. That is the shape this cycle established, and every fast-mana conversation since has been measured against the precedent it set. The unconstrained version, the one that simply enters and adds a color, was understood within a year of printing to be a mistake the game could not afford to repeat, so the successors all bolt a constraint onto the same chassis. Sol Ring charges a mana to cast and pays back colorless. Chrome Mox demands an imprint. Mox Opal demands metalcraft. Mox Amber, Mox Tantalite, and Mox Diamond each carry their own toll. Because the original mox can never come back into print, the design space around it has stayed unusually busy: Wizards keeps releasing variants that probe how close they can get without breaking a format again. The red one specifically fuels the turn-one threats that most reward a mana ahead before the opponent has untapped: Goblin Guide, Grim Lavamancer, the old Sligh curve. The Power Nine label reads as marketing, but the underlying logic is simpler and more durable. This is a baseline, not a card.