Celestial Prism

Five total mana to produce a single colored mana: three to cast it, then two more and a tap every time you want to draw on it. That rate looks absurd from any modern vantage, but it documents a specific design anxiety of the earliest sets, where a colorless source of every color was treated as a load-bearing privilege that had to be priced into oblivion. Wizards had not yet decided how aggressively artifacts should be allowed to break the color pie, and "add one mana of any color" was a sentence the design was still nervous to print. Trace the effect forward through Chromatic Sphere, Chromatic Star, Prismatic Lens, and eventually the talisman and signet cycles and you get a thirty-year argument about how cheap that effect can safely be, with this sitting at the expensive extreme of it. It does not see play because every card printed since has done the job for less, but it remains a useful historical marker: the moment when universal fixing was a privilege Wizards charged for in full.