You're not far off.
Elvira is a horror movie host, she hosted a late night movie show that showed old shclocky b movies & whatnot.
The personality grew so famous that they gave her a movie, which is also b movie schlock, but its wonderfully kitchy & funny.
Too Macabre – The Making of Elvira: Mistress of the Dark – 2018 version of this feature-length documentary on the making of the film, including interviews with various cast and crew and rare never-before-seen archival material
Recipe for Terror: The Creation of the Pot Monster – 2018 version of this featurette on the concept and design of the pot monster, as well as the film’s other SFX
Extensive image galleries
Original US theatrical and teaser trailers
Limited edition Steelbook featuring newly produced artwork
Limited edition booklet featuring a foreword by writer and director Sam Irvin and writing on the film by Kat Ellinger and Patterson Lundquist