The actual Blob, a mixture of red dye and silicone, has never dried out and is still kept in the original five-gallon pail in which it was shipped to the production company in 1958 from Union Carbide. It was put on display over the years as a part of the annual Blobfest, held over a three-day period each summer in Phoenixville, PA, which provided a number of the shooting locales for the film. In addition to displaying the Blob and miniatures used in the shooting, the event features a reenactment of the famous scene in which panicked theatergoers rush to exit the town's still-functioning Colonial Theater, as well as several showings of the film.
Steve McQueen was offered $2,500 or 10% of the profits. He took the $2,500 because the film wasn't expected to make much. It ended up grossing over $4 million. According to producer Jack H. Harris when being interviewed by film historian Tom Weaver, the film ultimately grossed $40 million.
The strange movie being shown in the theater was not a phony created for this film. It was an actual movie originally released as Dementia (1955). The scenes shown are from the re-cut version titled "Daughter of Horror", which had narration added. The voice doing the narration is that of Ed McMahon.
The title song "The Blob" was co-written by Burt Bacharach and is on his album "Look of Love:The Burt Bacharach Collection." Paramount tapped Bacharach and Mack David (brother of Bacharach's usual writing partner, Hal David) to come up with a non-threatening theme that would prevent the faint of heart from going into nostril-flaring terror during the opening credits. Together they came up with "The Blob," a goofy musical creature that is one part "Temptation" to two parts "Tequila." Session singer Bernie Knee does the champagne-cork-popping honors by pulling his finger out of his cheek seven times. Only Ralph Carmichael's score received a screen credit, giving credence to the notion that the song was a last-minute addition. The Five Blobs turned out to be a phantom group that consisted of Bacharach, a bunch of musicians for hire and Nee, who tracked his voice five times to achieve that Boris Karloff-esque quality.
According to producer Jack H. Harris, director Irvin S. Yeaworth Jr. initially met Steve McQueen when the actor's wife Neile Adams was appearing in a short religious film Yeaworth was making. According to Harris, Yeaworth found McQueen to be "a dirty jerk, an opinionated pain in the ass," among other things, and reportedly kicked him off of the set after Adams' part was completed. Hopeful of signing 'Anthony Franciosa' for the lead in "The Blob," Harris attended a performance of "A Hatful of Rain" in which Franciosa was appearing, but when he saw understudy McQueen filling in for an ailing Ben Gazzara, the producer decided to sign McQueen to a three-picture deal. McQueen proved so difficult that rather than find an entirely new director and crew to work with him, Harris decided to shoot the two subsequent films, 4D Man (1959) and Dinosaurus! (1960), with other actors, a decision he ultimately regretted.
Although producer Jack H. Harris always claimed that this film cost $240,000 to produce, years later director Irvin S. Yeaworth Jr. said that the actual cost was only $120,000. Other sources list the budget as low as $110,000.
This independent production was originally picked up by Paramount Pictures for use on the bottom half of a double bill with Paramount's production, I Married a Monster from Outer Space (1958). Early marketing tests and initial bookings indicated that a larger share of the ticket buyers were coming for this film rather than the top-billed picture, so it became the main feature and more money was spent on its promotion.
This film was originally going to be called "The Glob." It was changed when it was discovered that cartoonist Walt Kelly had already used that title. According to producer Jack H. Harris, the film was titled "The Molten Meteor" when it was in synopsis form.
In changing the title from "The Glob" to "The Blob," producer Jack H. Harris has hoped that comedians would still pick up on it. As he predicted, many comedians mentioned "The Blob" during their routines. This resulted in this low budget movie getting many free plugs on national television.
Bart Sloane is credited for special effects. He also served as the art director and animator. He created the animated sequence and main title over which the cast and credits were matted. His other animated sequences included the shot of the electric cable being shot off of the pole and the live electric line striking the blob. He also created the matte paintings.
The old man's cabin and the crater were filmed in a soundstage. There were two versions of the cabin built. One was full size for the actors to use. The second version was only about three feet high and was used in the background of wide shots to create a false perspective.
According to producer Jack H. Harris, there were at least two proposed television series based on this film. None had made it to the pilot stage. Harris jokingly suggested that The Blob could become a good guy and solve crimes.