Something is Haunting Riverdale High Archie's Weird Mysteries : Season 1 Episode 19

Midge, Dilton, and Ethel aren't exactly the most popular of kids, so no one thinks much of it when they go missing. However, when Archie is rendered invisible and untouchable by one of Dilton's inventions, he finds that he must work with them to stop the haywire machine from turning Riverdale into a ghost town!