Obelisk of Alara

Six mana for an artifact that returns nothing on the turn it resolves, and then two more per activation: this is a payoff whose reward scales with how much of the five-color manabase you can assemble. The reward for paying that toll is one of the broadest single-card toolkits ever stapled to a noncreature permanent. Each ability keys to a different color, so the Obelisk is only as deep as your access is wide, and a deck that reliably makes all five colors turns it into a repeatable answer to almost any question the board poses: lifegain to outrun aggression, a loot to dig, a -2/-2 to clear a threat, a recurring three-point reach to the dome, and a combat pump. The real throttle is the tap symbol. Every ability shares the same activation, so however much mana you have to burn, the Obelisk answers exactly one question per turn cycle and then sits inert until it untaps. That single-use-per-turn clamp is what keeps a five-color toolbox from collapsing into a do-everything engine: the card forces you to choose, in sequence, which problem matters most right now. This is a greedy, mana-hungry value engine that rewards a deck for already being fixed rather than fixing it for you, a payoff for the kind of board state where you have mana to spare and no obvious best use for it.