Voidstone Gargoyle

Most hatebears name a category; this one names a single card and shuts it off at the root. The choice happens once, on entry, and it answers two questions at the same time: spells with that name can't be cast, and activated abilities of sources with that name can't be activated. That second clause is what elevates it from a counterspell-on-a-stick to a genuine prison piece, because it reaches permanents already on the battlefield. Name an opposing planeswalker's troublesome value engine, an artifact's tap ability, a creature's machine-gun activation, and the thing keeps sitting there doing nothing. The cost of that precision is rigidity: the name is locked in for as long as the Gargoyle lives, so a wrong guess against a deck you've misread leaves you with a 3/3 flier whose static lock points at nothing, and a savvy opponent simply pivots to a redundant copy under a different name. It rewards knowing the metagame down to the card, not the archetype: you are not hating "their combo," you are hating one named piece of it. White rarely interacts with the stack at all and almost never pre-empts an ability, so the design hands the color a borrowed job, trading the open-endedness of true countermagic for a body in the air and a permanent declaration. Flying does real work in that bargain: it lets the lock close games rather than just stall them, turning a static lockdown into a clock.