Vermicious knids are monsters that are portrayed as being able to shape-shift into anything they please. They appear in the 1972 book Charlie and the Great Glass Elevator, and only mentioned in the 1971 film Willy Wonka and the Chocolate Factory.
In the book, Mr. Willy Wonka states that "Vermicious knids are the terror of the universe. They travel through space in great swarms, landing on other stars and planets and destroying everything they can find. There used to be some rather nice creatures living on the moon a long time ago. They were called Poozas. But the Vermicious knids ate the lot. They did the same thing on Venus and Mars and many other planets." He also goes on to say that none have made it to Earth because they get burned up when they reach Earth's atmosphere, and he says that's what shooting stars really are. Mr. Wonka considers them "show-offs" after shaping into the words "SCRAM".