Stinkbug Blocker

Put one inside a finished room and the game stops treating that room as somewhere an NPC will move into. Everything else about the housing still checks out, so you can build a whole town in advance, block every room, then remove blockers one at a time to decide exactly who lives where. That control is the point. It beats leaving rooms unfinished or ripping doors out to keep people from settling in the wrong place.

The housing query tells you when one is working. Point it at a blocked room and it reports an infestation instead of the usual verdict, which is how you find the blocker you forgot about.

The Ghostly Stinkbug Blocker does the same job and cannot be seen once placed. To spot it you need Spectre Goggles equipped or an active Echo Chamber nearby, the same rule that governs Echo Blocks. Use it when a bug stuck on the wall would ruin a room you spent real time on, and accept that a forgotten one is genuinely hard to hunt down later.

Cats, dogs and the other town pets are not affected and will happily settle in a blocked room. That gives you a clean way to reserve a space that only a pet can ever occupy.