These shape-changers, Wonka tells the others, are predatory extraterrestrials called Vermicious Knids, waiting in the Space Hotel to consume its staff and guests. Wonka also explains that the Knids have tried to invade Earth and consume its inhabitants like they have done with many other planets (Mars, Venus and the Moon, among others) but are always incinerated because of the atmosphere protecting the planet. "That's what actually causes most of those fiery streaks that you call 'shooting stars' --- they're really speeding Knids trying to enter the atmosphere," Mr. Wonka informs Charlie.