There's something wrong with the Whateley boy. This 1970 adaptation of the Dunwich Horror was produced by Roger Corman, which should say everything you need to know. It's a very loose treatment of the short story, which is mostly a history of the Whateley family with a big ol' monster battled added onto the end. The movie, instead, makes the story about seduction and abduction, but the plan remains: summon Yog-Sothoth at all costs.