Prophetic Prism

The standard against which every cantripping mana rock is measured. The pitch is austere by design: pay two, replace itself with a card, and from then on filter colorless mana into any color for one mana a pop. That filtering clause, not the fixing rate, keeps the card relevant. It does not ramp; tapping for one to produce one is a wash in raw mana count. What it does is launder colorless or off-color sources into exactly the pip a greedy spell demands, while the enters-the-battlefield draw means the slot never costs you a card. That combination (color correction plus cantrip) is the niche it owns, and the lineage runs straight through it: later designs like Chromatic Star and Chromatic Sphere went the cheaper, one-shot route, trading repeatability for a lower floor, while this trades the floor for a permanent that keeps fixing turn after turn. The cantrip is what keeps the inclusion honest. A pure filtering rock with no immediate impact is a tempo liability; the replacement draw means the worst case is paying two mana to draw a card on a board state that did not need the fixing yet. Unglamorous, low-ceiling, and exactly the kind of connective tissue that holds together decks running more colors than their lands can comfortably support.