The special takes place on Halloween, when Gonzo is challenged to spend the night in The Haunted Mansion. According to Disney's announcement, the special features "a star-studded Muppets cast, celebrity cameos, all-new music and spooky fun for families to enjoy together."
The special features three new original songs - "Rest In Peace," "Life Hereafter," and "Tie the Knot Tango," along with a cover of "Dancing in the Moonlight" and the attraction's trademark song "Grim Grinning Ghosts." An EP of songs from the production was released concurrently with the special's premiere.
Rather than attending the Muppets' annual Halloween party, Gonzo and Pepe are en route to participate in a fear challenge event in the mansion where Gonzo's favorite magician, The Great MacGuffin, disappeared. Upon being dropped off by their driver (Yvette Nicole Brown), Gonzo and Pepe meet the caretaker (Darren Criss), along with several ghosts and singing busts outside the mansion who perform "Rest In Peace."
The duo is then greeted by their "Ghost Host" (Will Arnett) who informs them that Gonzo was invited there to see if he can survive one night inside this haunted mansion. And if they cannot, they will be trapped there forever. While Gonzo claims that he is afraid of nothing, Pepe is scared by everything he sees. The two explore the mansion and, after meeting Madam Pigota, Gonzo and Pepe come across a room full of several ghosts resembling their Muppet friends who put on a vaudevillian-esque show entitled The Mansion Show (featuring At the Dance style jokes, the stand up comedy of Gauzey the Hatbox Bear, and a performance of "Life Hereafter"). The host reappears and informs Gonzo that in order to survive his time in the mansion he must face his fears in Room 999.
As Gonzo is led off to the room, Pepe meets and becomes entranced by the mansion's resident bride Constance Hatchaway (Taraji P. Henson). It is revealed via song in the "Tie the Knot Tango" that she plans to marry Pepe and then, as explained by the ghosts of her past husbands, kill him.
Gonzo enters Room 999 and faces his biggest fear: that no one will like him if he does not continue to do dangerous stunts. Gonzo starts to turn old as his reflection taunts him, but recalling a conversation with Kermit that he had earlier, Gonzo realizes that he can be great by just being Gonzo and, upon looking out at the party he's missing, he realizes that his bigger fear is losing his friends (and no stunt is worth that). Gonzo rejects the allure of the mansion and its challenge and is ready to leave to reunite with his friends.
The host appears to congratulate Gonzo for facing his fears and tells him that he is free to go. But upon realizing that sunrise is approaching and that Pepe is in trouble, Gonzo refuses to leave the mansion without him. With the help of the host's candelabra, Gonzo is able to find Pepe and stop the wedding. The pair jump out the window and make it out of the mansion just as the sun rises. The host meets them outside, revealing himself to be the ghost of the Great MacGuffin, and is impressed that Gonzo was willing to do what he could not - face his fears. The pair are picked up by their driver and head off to meet the rest of their friends for a post-Halloween breakfast as "Dancing in the Moonlight" plays on the car's radio and a rainbow appears in the sky.
- Gonzo as himself
- Pepe the King Prawn as himself
- Miss Piggy as Madame Pigota
- Kermit the Frog as The Mansion Show host
- Fozzie Bear as Gauzey the Hatbox Bear
- The Electric Mayhem (Dr. Teeth, Floyd Pepper, Janice, Zoot, Lips and Animal) as Madame Pigota's band
- Chip as Pickwick (chandelier ghost)
- Robin the Frog as the Birthday Ghost
- Sam Eagle and Pops as the Duelists
- Rowlf the Dog as the Organist
- Happy Haunts: Scooter, Wayne and Wanda, Clean Gene, Beautiful Day Monster, Big Mean Carl, Crazy Harry, Mo Frackle, J. G., Statler and Waldorf, Bobo the Bear, Beverly Plume, The Swedish Chef, Howard Tubman, Marvin Suggs, Nigel (Muppet Show), Nigel (Muppets Tonight), Joe from Legal, Pokey, Mulch, Dr. Phil van Neuter, Miss Cartier, Squid Ghost, Chickens, Frackles, Skulls, Ghosts
- Constance's Husbands: Johnny Fiama, Sal Minella, Walter, Beauregard, Lew Zealand, and a Penguin
- Uncle Deadly as the Justice of the Peace
- Andy and Randy Pig as the Grady Twins
- Dr. Bunsen Honeydew and Beaker as the Staring Busts
- Rats: Rizzo, Bubba, Yolanda, Ballroom Rat
- The Caretaker's Dog
- Mummy and Duddy
- Screaming Goat
- Monster Plant
- Stairway Monster
- Pee Wee
- Halloween Party Attendees
- Kermit (dressed as Piggy)
- Miss Piggy (dressed as Kermit)
- Scooter (dressed as Elvis)
- Lew Zealand (with an arrow through his head) and a Boomerang Fish (dressed as Lew)
- Fozzie Bear (dressed as a banana)
- Chip (dressed as a robot)
- Clean Gene (dressed as a bunny)
- Cactus (dressed as Santa Claus)
- Floyd Pepper (dressed as a clown)
- Beautiful Day Monster
- The Swedish Chef (dressed as he did in The Walking Bread parody)
- Party Tomatoes
- Muppet Art and Decorations
- Changing portraits: Yolanda, The Newsman, Dr. Phil van Neuter, Annie Sue and Gaffer
- Stretching room portraits: Janice (tightrope), Crazy Harry (dynamite), Link Hogthrob, Dr. Julius Strangepork, Miss Poogy (quicksand)
- Gargoyle candle holders: Mahna Mahna and the Snowths
- Room 999: Doglion (door decoration)
- Cups: Angel Marie
- Muppet Performers
- Dave Goelz, Bill Barretta, Eric Jacobson, Matt Vogel, Peter Linz, David Rudman, Julianne Buescher, Alice Dinnean, Bruce Lanoil, Brian Henson
- Human Cast
- Will Arnett as the Host (The Great MacGuffin)
- Taraji P. Henson as the Bride
- Darren Criss as the Caretaker
- Yvette Nicole Brown as the Driver
- Singing Busts:
- John Stamos as Famous Person
- Kim Irvine as Haunted Mansion Maid
- Quinn McPherson as Hallway Knight
- Director: Kirk R. Thatcher
- Teleplay: Bill Barretta & Kirk R. Thatcher & Kelly Younger
- Story by Bill Barretta & Kirk R. Thatcher & Kelly Younger and Jim Lewis
- Music by Ed Mitchell, Steve Morrell
- Producers: Chelsea DeVincent, Michael Steinbach
- Executive Producers: Bill Barretta, Andrew Williams, David Lightbody, Leigh Slaughter
- Co-executive Producers: Kelly Younger, Jim Lewis
- Director of Photography: Craig Kief, A.S.C.
- Production Designer: Darcy Prevost
- Editors: Alexandra Amick, Jason Bierfeld
- Costume Designer: Lisa Davis
- Post-production & Visual Effects Supervisor: Brooke Stone
- Casting: Tony Shephard
- Muppet Workshop
- Puppet Captain: Bill Barretta
- Workshop Supervisor: Jane Gootnick
- Workshop Technicians: Gretchen Crookes, Tim Lagasse, Tomas Seidita
- Muppet Designers & Builders: Puppet Heap, LLC
- Supervisor: Paul Andrejco
- Production Coordinator & Senior Artist: Peter MacKennan
- Art Director: Lauren Attinello
- Muppet Coordinator: Danielle Obinger
- Costumer: Sally Thomas
- Lead Builders: Mary Brehmer, Michael Busch, Isabelle DuFour, Henri Ewaskio
- Builder: Matt Brennan
- When Gonzo recalls some of his past stunts, footage from The Muppets episode "Going, Going, Gonzo" and episode 106 of Muppets Tonight are used.
- Johnny Fiama and Sal Minella make their first on-screen appearance since the 2009 "Bohemian Rhapsody" music video. The special marks Brian Henson's first performance with the Muppets since 2005's The Muppets' Wizard of Oz.
- Early in production, a scene was planned involving Dr. Phil van Neuter, Mulch, Bunsen, and Beaker in a lab examining the inside of Gonzo's head. Due to time and budget constraints, the scene was ultimately scrapped and the characters were placed elsewhere in the special.
- Many of the costumes used for the characters were previously used in earlier films and specials. Most of the ghosts used costumes from The Muppet Christmas Carol. 
- Gags were considered for a number of characters who ended up not appearing, including Bean Bunny, Bobby Benson, and Thog.
The project initially began in late 2019/early 2020, with full production intended to take place in March 2020. Due to the COVID-19 pandemic, it was suspended until much later that year. The special then began shooting over the course of three-and-a-half weeks in April 2021. Prior to the pandemic shutdown, the proposed version of the special was to run 90 minutes instead of the finalized 50-minute special.
The project was announced in May 2021 as part of Disney's "Halfway to Halloween" event with a special video featuring Gonzo and Pepe the King Prawn.
The Fall 2021 issue of Disney twenty-three includes a feature on the special, entitled "A Gonzo Halloween." The article includes interviews with The Muppets Studio vice president Leigh Slaughter, Gonzo, and Pepe the King Prawn.
Chocolate eclairs promoting the special sold at PizzeRizzo starting on September 1st revealed Muppet versions of three of the Stretching Portraits, with Crazy Harry being placed into the role of the Dynamite Man, Link Hogthrob, Dr. Julius Strangepork, and Miss Poogy as the quicksand trio, and Janice as the tightrope walker. A fourth eclair features a Muppet version of the Haunted Mansion's iconic wallpaper.
Further promotion in the Disney theme parks included a "Magic Moment" photo-op at the Haunted Mansion in Disney World, where the Muppet Haunted Mansion logo and Piggy as Madame Pigota are superimposed into the guest's photograph. Exclusive footage from the special was also screened as a part of the Muppet*Vision 3D pre-show starting September 30. In Downtown Disney in California, a promotional display area was set-up featuring artwork, props, and a specially-decorated truck. "The Art of the Haunted Mansion," an exhibition housed at "Great Moments With Mr. Lincoln," in Disneyland, began displaying various props from the special starting in October.
The first footage from the special was featured in a promotional video for Disney+'s "Hallowstream" celebration, published on September 8.A full trailer followed on September 23.
The special received its world premiere at the Disney+ Hallowstream Drive-In on October 7 (a cast and crew-only event), which featured a live introduction by Gonzo and Pepe the King Prawn; a public screening was held on October 9 (paired with Behind the Attraction: The Haunted Mansion and The Muppet Show: "Vincent Price").
- August 29, 2021
- October 5, 2021
- October 6, 2021
- Taraji P. Henson on Good Morning America, showing a clip of "Tie the Knot Tango."
- Pepe the King Prawn on Wheel of Fortune, and "The Spin with Maggie Sajak"
- Darren Criss, Yvette Nicole Brown, Miss Piggy, and Gonzo on ABC News. 
- Miss Piggy on Collider
- Pepe and Yvette Nicole Brown on The Nerds of Color
- Miss Piggy and Gonzo and Pepe on Everything Iconic with Danny Pellegrino
- Miss Piggy on The Nerdist 
- Miss Piggy on Associated Press
- Miss Piggy, Gonzo, and Yvette Nicole Brown on Reuters
- Miss Piggy and Darren Criss on LRM Online
- October 7, 2021
- Miss Piggy, Gonzo, and Pepe the King Prawn on D23 social media
- Gonzo and Pepe on the D23 Inside Disney podcast 
- Miss Piggy, Andrew Williams, and Leigh Slaughter on Beyond the Mouse 
- Pepe the King Prawn and Gonzo on Tough Pigs 
- Gonzo and Yvette Nicole Brown on LRM Online
- Gonzo, Miss Piggy, and Yvette Nicole Brown on SYFY Wire
- Miss Piggy, Gonzo, Darren Criss, and Yvette Nicole Brown on E! News
- Pepe the King Prawn and Yvette Nicole Brown on Collider
- Gonzo and Pepe the King Prawn on Disney+ social media
- Miss Piggy and Pepe & Yvette Nicole Brown on Screen Rant Plus
- October 8, 2021
- Miss Piggy, Pepe the King Prawn, and Yvette Nicole Brown talk to Decider 
- Gonzo & Yvette Nicole Brown and Miss Piggy & Darren Criss on Good Morning America
- Miss Piggy on QueertyTV 
- Miss Piggy, Gonzo, Pepe, Darren Criss, and Yvette Nicole Brown on Disney social media 
- Gonzo, Pepe, and Yvette Nicole Brown on Disney+ Twitter notification 
- Performers Dave Goelz and Bill Barretta on WD-FM
- October 9, 2021
- October 12, 2021
- Gonzo and Pepe on Dancing with the Stars
- October 13, 2021
- Pepe on Good Morning America
- October 20, 2021
- Gonzo, Pepe, and Miss Piggy on Disney Movie Insiders Presents
- "Muppets Haunted Mansion" Halloween Special Premieres This Fall On Disney+ May 7, 2021
- The Barretta Brothers: Ep #49 Haunted Mansion Live Q&A! (00:12:15)
- The Barretta Brothers: Ep #49 Haunted Mansion Live Q&A
- Thatcher, Kirk Twitter post
- The Muppet History Podcast: Episode 6 - Kirk Thatcher and Muppets Haunted Mansion (00:07:44)
- Kirk Thatcher on Reels of Justice (00:04:37)
- @craigkief_asc Sep 3, 2021
- Craig Kief - About
- Disney Information Station "Muppets Haunted Mansion Chocolate Eclair Debuts" by Deni Sunderly, Sept 1, 2021
- WDW News Today "Muppets Haunted Mansion Éclair...at PizzeRizzo" by Matthew Soberman, Sept 1, 2021
- Disney Theme Parks Celebrate Muppets Haunted Mansion Tough Pigs, September 24, 2021
- Downtown Disney Gets Muppet Haunted Mansion Display Tough Pigs, October 3, 2021.
- Disney+ Hallowstream Drive-In
- The Walt Disney Family Museum: Muppets Haunted Mansion with Muppet Performers Dave Goelz and Bill Barretta