I had a book about dinosaurs as a child that must have been from the 70's. In it they said that large dinosaurs had a second brain in their pelvis because their brains were so small that they needed two in order to function.
I believed that shit for a long, long time. It turns out that paleontologists believed it for a while too, but later found out that dinosaurs just had unusual pelvic bones. Well, nobody told me and I wound up looking like an idiot when I told my wife that dinosaurs had a second brain in their ass at the museum.