The Demon Box, also known as The Fantabulous Demon Wonderbox, is one of the items sold at Weasleys' Wizard Wheezes. It apparently contains one or more demons. A label on the packaging warns buyers not to feed anything that comes out the box after midnight, lest it multiply and begin to savage people.
Behind the scenes
- The warning not to feed the demon after midnight may be a reference to the film Gremlins, where a similar warning was given about Mogwai (the gremlins referenced in the film's title).