SpongeBob's Adventures of Muppet Treasure Island is an upcoming SpongeBob/Muppets crossover to be created by Tiffy33.
Jim Hawkins is a young orphan living with his friends Gonzo and Rizzo at the Admiral Benbow inn in England. Dreaming of sea voyages, Jim only has the tales of Billy Bones (to help, Bones telling Jim and the inn patrons of Captain Flint, his old captain, burying his treasure on a remote island and killing all of his crew, and that no one knows the whereabouts of the map. One night, as Jim, Gonzo, and Rizzo continue to dream of sea voyages, Bones' fellow pirate Blind Pew arrives and gives Bones the black spot. Bones dies of a heart attack but reveals to Jim, Gonzo and Rizzo he had the map all along beforehand. Blind Pew returns with an army of pirates, but the boys escape with the map.
Going to a harbor town, the boys meet the half-wit son of Squire Trelawney who decides to fund a voyage to find Treasure Island and Flint's fortune. Accompanied by Dr. Livesey and his assistant Beaker, the boys and Trelawney hire the Hispaniola, commanded by Captain Abraham Smollett (Kermit the Frog) and his overly strict first mate Mr. Arrow. The boys meet the cook Long John Silver, a one-legged man who Bones warned the boys about before dying. The ship sets sail, but Smollett is concerned by the pirate-like crew, learning they were hired on Silver's suggestion. Jim and Silver bond, but Gonzo and Rizzo are captured by the pirates Polly Lobster, Mad Monty, and Clueless Morgan who demand they surrender the map; before Mr. Arrow catches them in the act and imprisons them in the brig. Smollett locks the map in his safe upon ordering Jim to give him the map for safekeeping.
Eventually, after all members of the crew battle against the tedium of a becalmed sea, it becomes apparent that Silver is leader of the pirates and plots a mutiny, fooling Mr. Arrow into leaving the ship to test a lifeboat for safety precautions, a lifeboat Silver has sabotaged to sink. Jim, Gonzo, and Rizzo learn of Silver's plan and inform Smollett. Smollett planned to leave Long John Silver and those involved on Treasure Island. However, Silver tricks Jim into joining him upon arrival at Treasure Island with the other pirates stealing the map from Smollett's safe. Smollett, Gonzo, and Rizzo go to save Jim but are captured by the local tribe of native pigs ruled over by Benjamina Gunn, Smollett's ex-fiancée who he left at the altar. Jim, Silver, and the pirates find the hiding place of Flint's treasure only to find the treasure missing. Silver then sends Jim away as a fight breaks out among the pirates. The pirates come across Smollett and Benjamina. Smollett is then suspended from a cliff until Benjamina tells Silver the treasure is hidden in her home, but when Benjamina spits out a kiss from Silver, he leaves the two to dangle, allowing the pair to fall in love again.
Jim, Gonzo, and Rizzo find Mr. Arrow, who escaped the sabotaged lifeboat, and he aids them sneaking on board the ship and scaring off the pirates still onboard by posing as his ghost and freeing Trelawney, Dr. Livesey, and Beaker, before the figureheads of the Hispaniola save Smollett and Benjamina. A battle breaks out between the heroes and the pirates where Sweetums defects to Smollett's side and takes out some of the pirates. Smollett then fights Silver in a sword battle but loses. Jim and the others rally to their captain's aid, resulting in Silver surrendering honorably. All the pirates are stuffed into the brig, but Silver escapes using Mr. Arrow's keys. Jim catches him in the act but ultimately allows Silver to leave for the sake of their previous friendship, though he renounces it henceforth, calling him "Mr. Silver" and concealing his emotion at their final farewell. However, Mr. Arrow informs Jim and Smollett that the longboat Silver took was unsafe, forcing Silver to abandon ship and swim to Treasure Island the next day. The crew of the Hispaniola sail off into the sunset while some scuba-diving rats discover the treasure.
During the credits, it is revealed that Silver is eating a banana, marooned on the island with only a wisecracking Moai head for company as the Moai tells him a bad joke.
- Anna, Elsa, Olaf, Kristoff, Sven, Surly, Buddy, Grayson, Andie, Precious, Mole, Jimmy, Johnny, Raccoon, Vinny Griffin, The Powerpuff Girls (Blossom, Bubbles and Buttercup), Phineas, Ferb, Candace, Isabella, Baljeet, Buford, Perry, Dr. Doofenshmirtz, Homestar Runner, Strong Bad, The Cheat, Strong Mad, Strong Sad, Pom Pom, Marzipan, Coach Z, Bubs, The King of Town, The Poopsmith, Homsar, Thomas, Edward, Henry, Gordon, James, Percy, Toby, Emily, Dipper, Mabel, Wendy, Leo, June, Quincy, Annie, Barney, BJ, Baby Bop, Bloo, Mac, Frankie, Wilt, Eduardo, Coco, Jake, Izzy, Cubby, Skully, Chicken Little, Abby Mallard, Runt of the Litter and Fish Out of Water guest star in this film.