The death of the projectionist causes panic in the theatre. The film featured is Dementia, a strange mystery film with no dialogue, which was recut and presented with additional voice-over, renamed as Daughter of Horror – poster and marquee can be seen in the last screenshot. Nevetheless, it gained access only in limited theatres, but the fact that being featured in The Blob finally made it a well-known film.
John Parker’s Dementia (1955) in Irvin S. Yeaworth Jr.’s The Blob (1958).
The scene outside the theatre, where the marquee and the poster of Daughter of Horror are visible, is also featured in the trailer of The Blob, as seen in the drive-in scene of Grease (1978).