“Sesame Street” creators on Thursday filed a lawsuit against STX Entertainment, alleging that its marketing campaign for “The Happytime Murders,” an R-rated Melissa McCarthy film featuring naughty and foul-mouthed Henson puppets, tarnishes the “Sesame Street” brand.

The film centers on the story of a puppet cast from a 1980s television show that begins to get murdered one by one, prompting a police investigation that ropes in McCarthy’s character and her puppet partner to look into the homicides.

Brian Henson, son of the late Jim Henson, directed the picture and the Jim Henson Company also helped produce.

The trailer, released recently, and other promotional materials make clear the film is not kid-friendly, showing scenes of drug use, sex, and other foul behavior by puppets with a tagline that reads: “No Sesame. All Street.”

But “Sesame Street” creators are incensed at the reference, arguing in the lawsuit that it will confuse audiences and harms the “Sesame Street” brand. The marketing campaign “seeks to capitalize on the reputation and goodwill of ‘Sesame Street,’” the suit says. “While the trailer at issue is almost indescribably crude, ‘Sesame’ is not trying to enjoin defendants’ promotion or distribution of their movie. It is only defendants’ deliberate choice to invoke and commercially misappropriate ‘Sesame’s’ name and goodwill in marketing the movie — and thereby cause consumers to conclude that ‘Sesame’ is somehow associated with the movie — that has infringed on and tarnished the ‘Sesame Street’ mark and goodwill.”

Filed in New York, the lawsuit also contains screen captures of social media reactions. One tweet read, “I’ll never look at muppets/sesame street the same way.” According to the suit, Sesame Workshop, the nonprofit behind the television show, sent a letter on May 18 to in-house counsel of STX and the Jim Henson Company, which is a producer on the film, demanding they stop making references to “Sesame Street” in the marketing materials.

An STX spokeswoman on Friday issued a tongue-in-cheek response, attributing the company’s statement to a fictional puppet named Fred, Esq. “STX loved the idea of working closely with Brian Henson and the Jim Henson Company to tell the untold story of the active lives of Henson puppets when they’re not performing in front of children,” the statement said, in part.

It continued: “While we’re disappointed that ‘Sesame Street’ does not share in the fun, we are confident in our legal position. We look forward to introducing adult moviegoers to our adorably unapologetic characters this summer.”

“The Happytime Murders” is scheduled to hit theaters Aug. 17. Todd Berger wrote the screenplay. In addition to McCarthy, the film stars Elizabeth Banks, Maya Rudolph, and Joel McHale.