Doug Inc. / Doug's Nightmare on Jumbo St. - S3-E10
Continuity mistake: Doug's Nightmare on Jumbo Street: When Doug has a nightmare about the Abnormal, he runs into his garage, and the doorknob is visible on the door. When he shuts the door and leans against it, the doorknob is suddenly gone. It comes back in the next shot. (00:16:06)