Kuswort is a fan-created plant from the Harry Potter fandom. Ironically, it is the essential ingredient in the cure for the Mary Sue disease, Vambiolaria, which was created by a fan-made spell gone horribly, horribly wrong. The plant was discovered and put to use at the Hogwarts Fanfiction Academy.
Kuswort has yellow foliage and smells like vomit. Its spores are difficult to cultivate out of season. They tend to explode into vomit-scented mist, but may also produce other effects, such as singing nasty versions of songs (e.g. "Frosty the Snowman") or shooting colorful fumes that resemble fireworks. The fumes are noxious and cause hallucinations.