Tasigur's Cruelty

Mind Rot has been the baseline two-card discard spell for as long as the effect has existed, and the printed rate (six mana for two cards) is almost insulting on its face. Delve is the entire bargain: it converts spent spells, fetched-away lands, and dead creatures into a discount, so the sticker price is a ceiling you almost never pay. Stock a graveyard early and this resolves on turn three or four for two or three actual mana, gutting a hand before an opponent has committed to a plan. The tension is the same one delve always creates: every card exiled to cast this is a card you are not flashing back, not reanimating, not feeding to a later delve spell. It rewards a deck that treats the graveyard as fuel to be spent rather than a resource to hoard, and it punishes the greedy by quietly raising the price every time you hold it. As discard goes, the effect is plain; what earns it a slot is the arithmetic, where the difference between a six-mana brick and a two-mana hand-rip is entirely a function of how much you have already cast.