Agonizing Memories

The tempo-loss school of hand disruption, where the cards never actually leave: instead of stripping two cards to exile or graveyard the way discard usually works, this puts them back on top of the library. That distinction is the whole design. A discard spell trades your card for theirs one-for-one and is done; this blanks the opponent's next two draw steps entirely, since both of those draws will be cards you chose for them out of their own hand, and lets you order them so the worse one comes first. Against a combo piece or a top-end threat you can see coming, you bury it under itself and stall the clock while they spin their wheels. The cost of the trick is that it is information without removal: the cards are still in the deck, the opponent reaches them eventually, and a single shuffle effect or a Brainstorm-style rearranger unravels the work entirely. The price is steep for a spell that does no permanent attrition, which makes it a narrower tool than the discard staples it shares a color with. But the design question it asks (how much is delay worth when you also get to peek?) is a clean and unusual one for black, which more often answers threats by destroying them outright.