Excommunicate

Bounce-to-top is the most temporary form of removal white has ever been allowed to run cleanly. Where Unsummon and its kin return a creature to hand and let the opponent recast at leisure, sending it to the top of the library is a harsher tax: the owner draws their creature back instead of a fresh card next turn, eating an entire draw step to undo the disruption. That single-card cost is the toll the rate collects. The structural weakness is the inverse of the same fact: against a recurring threat it buys only one turn, since the thing is right back in hand the moment they draw. The exception is instructive. Point it at a token and the effect becomes permanent: a token that leaves the battlefield for any other zone, the library included, ceases to exist as a state-based action, so a top-deck stuffer quietly turns into a clean kill spell against creatures with no card backing them. White is the color most often denied true creature removal at this price, and a sorcery-speed library-stuffer is the compromise the design space tends to offer instead: a tempo swing dressed as an answer, useful for blunting a haymaker, stranding a reanimation target, or erasing a token outright. The window it opens is narrow and entirely proactive, which is why this kind of card lives and dies on whether a turn of breathing room is worth a full card.