Glasses of Urza

One mana buys you a permanent that does nothing but watch: tap it to read an opponent's hand, then tap it again next turn to read it again. That premise comes out of an early school of design that treated information as a resource scarce enough to build a dedicated artifact around. The original designers thought knowing what an opponent held justified spending a card slot on the knowing alone, with no board impact attached. Modern Magic has since folded hand-knowledge into cantrips, discard spells, and triggered peeks, all of which deliver the same data while also advancing your board, your hand, or your tempo. The Glasses, by contrast, ask you to commit a permanent and then spend a tap each turn for the privilege of looking, and the repeatability was the only thing the design ever had going for it. It was never enough: the information degrades the instant the opponent draws, and the artifact does nothing about whatever you find. Every later card that prints "look at target player's hand" as a rider on something else is, in a sense, an admission that the look was a slot too expensive to justify on its own.