Charmed Pendant

Mana ramp that pays out in whatever colors your deck happens to be milling away, which is a strange and self-consuming bargain: every activation feeds the graveyard one card while feeding the manabase whatever pips that card carried. The output is unpredictable by design, because it reads off the milled card's printed mana cost rather than producing a fixed color or amount, so a multicolor card off the top can ramp hard while a colorless artifact or a land yields nothing at all. That variance is what keeps it a curiosity rather than a real mana rock, and the "activate only as an instant" clause does not help its case: rather than enabling the usual hold-up play that every mana ability already allows, it strips away the one timing edge ordinary rocks keep, the ability to tap for mana mid-cast, in the middle of paying for a spell. It belongs to the era when designers were still mining the library itself as a resource pool, treating milling as something you might want to do to yourself rather than purely as a clock against an opponent. It cannot ramp without milling, and the colored symbols printed on the milled card are the only thing that determines whether the activation mattered: rules text, color indicators, and everything else color identity would count are irrelevant here. A four-mana rock whose payoff is a coin flip on your own deck's composition was never going to be a staple, but it is a genuinely odd piece of design.