“Cursed” times with mundane uses

I just had an idea to add items to a world that are considered by most to be cursed, but are really just something someone made for a practical purpose. The idea came up about an amulet that generates a cloud of darkness around the user’s head. It is sold as an amulet of protection to people an assassin’s guild is targeting, so that when they attack and the person activates the amulet, the cloud of darkness momentarily obscures their vision and confuses them. This is obviously something that only works on the gullible, and probably not that often, but the guild figures it’s worth a shot and they get some minor income.

The actual use it was designed for was a wizard who hated eye masks but couldn’t sleep if there was any light in his eyes, so instead of something pedestrian like installing curtains he made an artifact.

Any other ideas for items that could fit this mold?