Rats' Feast
The variable cost is the whole pitch: pay and exile exactly as many cards as your mana allows from one chosen yard, with no ceiling but the one your lands impose. (The sits on top of X, so clipping two cards costs three mana, not two.) That granularity sets it apart from the binary hosers it competes with. Tormod's Crypt and Nihil Spellbomb empty a graveyard wholesale or do nothing; this one charges by precision, shaving four flashback cards while leaving the rest, or peeling off a single reanimation target the turn before it would be cheated back. The single-graveyard restriction keeps the tool surgical rather than symmetric: even with several yards in front of you, you only ever drain one, so it is built for the scalpel. The constraint that bites is the type line. As a sorcery, it has no instant-speed window, so it cannot answer a graveyard the moment the stack threatens to spend it; you commit a main phase, on your turn, betting the relevant cards are still sitting there when you cast. What you buy for that timing tax is total control over both the price and the target, a dial the cheaper one-shots never offer. The flavor reads the same way: a feast content to eat one card or a dozen, billing by the mouthful.
