Dirty Bubble - A giant dirt bubble who is Mermaid Man and Barnacle Boy's number one arch nemesis and SpongeBob's favorite villain. He enjoys making his enemies eat dirt. When he first appeared, he tried to capture the heroes, who attempt to ditch SpongeBob. He successfully captured the two, before SpongeBob accidentally pops him with a pencil while attempting to get his autograph.The only way how to destroy the dirty bubble is to pop him with something sharp. Later, in "Mermaid Man and Barnacle Boy V", Dirty Bubble somehow returns. In the episode, Man Ray has teamed up with him to form an organization called E.V.I.L. (Every Villain Is Lemons). When Barnacle Boy tires of Mermaid Man treating him like a little kid, he joins the two, and commits crimes. In the end, Barnacle Boy returns to the good side, leaving Man Ray and Dirty Bubble disappointed. He is a champion at paddleball, as seen in "Have You Seen This Snail?". He was also shown in Back to the Past when Barnacle Boy showed SpongeBob and Patrick the dirty bubble wand. He blew the wand and popped the Dirty Bubble. His name might be derived from an episode in an old TV show called "The Wild Wild West" with an episode being named "Night of the Deadly Bubble." The Dirty Bubble was originally voiced by Charles Nelson Reilly and later voiced by Tom Kenny.
Man Ray - Man Ray was first mentioned in Mermaid Man and Barnacle Boy by SpongeBob when he's trying to get Mermaid Man and Barnacle Boy to come out of retirement. He later appears in person in "Mermaid Man and Barnacle Boy III", where SpongeBob and Patrick released him from frozen tartar sauce. When he discovers that he has a tickle belt, Man Ray tricks the duo to teach him kindness. After the class, Man Ray grabs the Aqua Glove and the Cosmic Ray from Mermaid Man and Barnacle Boy's arsenal to take over Bikini Bottom. When he discovers that he has become good, he quits villainy. However, the episode that he appears after the one he decides to become a nice headless man, he's evil again. He even used a flashlight to actually see two fish kiss. Then, he got arrested the next day after the Mermaid Man and Barnacle Boy became friends again. His head is made up of his mask/shoulder pads combo and is headless underneath that. Later, in "Mermaid Man and Barnacle Boy V", he becomes evil again (and somehow recovers his head), and brings back the Dirty Bubble and they team up with Barnacle Boy (who became evil) to form E.V.I.L. At the end, Barnacle Boy becomes good again, leaving Man Ray with Dirty Bubble in the middle of a long winded story.In Bad Guy Club for Villains he called Dirty Bubble Dirty. Additionally, even though he took off the Tickle Belt in Mermaid Man and Barnacle Boy III, he's shown wearing it in later episodes. In "Back to the Past", he took revenge. all old B Though it may be an Anti-Tickle Belt which allows him to continue to be evil.In Shuffleboarding (when's he good) it is acknowledged that he had a friend called Mable who went to high school with him. Man Ray also took her to the prom.He may be a parody of the Aquaman villain Black Manta. His name seems to be derived from the DC comics character Man-Bat and the American artist Man Ray, or the manta ray. Man Ray's original design was not of what he has been featured. In "Mermaid Man and Barnacle Boy," his original design is that of an actual manta ray as described of an episode SpongeBob recalls of him. John Rhys-Davies and Bob Joles voice Man Ray.
Atomic Flounder - A retired villain from 1952 who can blast hot radioactive beams from his mouth. Capable of third degree burns from his beams, he wears a radioactive suit and speaks with a Kennedy-esque New England accent. He is voiced by Carlos Alazraqui. Also seen in "The Bad Guy Club for Villains" voiced by Dee Bradley Baker. In this appearance, Atomic Flounder was lavender and his eyes are like aliens, a tail,. Just a thing used for box fights. Barnacle Boy said he could snap just like this. It is also known that he has an atomic touch so if he touches you you'll become atomic and the only way to reverse this is to make him touch you again. He is the only villain who is retired and who had aged. Also unlike the other villains and heroes on the show he is seen in plain clothes.
Kelp Thing - Seen in "Mermaid Man and Barnacle Boy VI - The Motion Picture". Kelp Thing is a humanoid, possibly human, covered with seaweed. He doesn't appear to have super powers and parks illegally, prompting Mermaid Man and Barnacle Boy to tow his car. In SpongeBob's Mermaid Man movie, he is represented by a piece of seaweed with goggle eyes who 'torments' Mermaid Man and Barnacle Boy by waving up and down on a string. Possibly a parody of DC's Swamp Thing or Marvel's Man-Thing.
Sneaky Hermit - A super hermit crab who plans to rule the world by means of sneakiness. He steals buildings in a sneaky fashion. His weakness is pepper. Seen in Lights, Camera, PANTS!. In the New Adventures of Mermaid Man and Barnacle Boy episode in that game, he called Man Ray, Moron Ray and the Dirty Bubble, the Dopey Bubble.
Snorelonn - Only mentioned in Nickelodeon Magazine, in the special SpongeBob issue. His evil plan is to wake everyone up with loud snoring noises. SpongeBob and Patrick were playing Mermaid Man and Barnacle Boy and said that Squidward was Snorelonn. He was possibly made up by SpongeBob and Patrick when they were playing Mermaid Man and Barnacle Boy.
Reflecto - Squidward was mistaken for Reflecto when SpongeBob and Patrick were playing Mermaid Man and Barnacle Boy. Reflecto uses mirrors in his evil schemes, and if he is ever cut off from sunlight, he loses his power. He was most likely made up by SpongeBob and Patrick when they were playing Mermaid Man and Barnacle Boy, mainly because SpongeBob refers to Reflecto as his "arch enemy." Reflecto might be real, because in SuperSponge, Barnacle Boy tells SpongeBob that "Reflecto has nothing on you."
Dr. Octofish - Barnacle Boy used his paddleball of fury to break this villain's concentration. Mentioned in Lights, Camera, Pants! Possibly the villain at the beginning of Mermaid Man and Barnacle Boy. "Doctor Octofish" is a possible parody of Doctor Octopus from Spider-Man.
The Moth - This villain appeared in "Night Light". He is a parody of the The Firefly. Voiced by Mark Hamill. There was also a villain in the first episode who appeared on the show; took a lollipop from a child, but was defeated with a whirlpool.
Drippy Bros. Studios - Created a Mermaid Man and Barnacle Boy movie, only they used actors and not the real Mermaid Man and Barnacle Boy.It may be a parody of Warner Bros. Studios
International Justice League of Super Acquaintances
The I.J.L.S.A. (International Justice League of Super Acquaintances) is a team of superheroes, who are aligned with Mermaid Man and Barnacle Boy. They were first mentioned in the episode Mermaid Man and Barnacle Boy V. In "The Bad Guy Club for Villains," SpongeBob and Patrick watch the Lost Episode of Mermaid Man and Barnacle Boy. In it, Mermaid Man and Barnacle Boy call their friends in what was then known as the "International Justice Lodge of Super Acquaintances," comprised of The Quickster, Captain Magma, The Elastic Waistband, Miss Appear, and The Pi-Right Ponderer. The villains were unfamiliar with these superheros, and so it can be certain that the name was later changed to the "International Justice League of Super Acquaintances," in which The Quickster joined up, and The Pi-Right Ponderer was never seen again.
Primitive Sponge - SpongeGar's ancestor. He has fangs from his upper jaw, a low brow and a brown loincloth. He is one of the first jellyfishers.
Primitive Starfish - Patar's ancestor. He has fangs from his lower jaw, a low brow and a green loincloth. He is one of the first jellyfishers.
Advanced Prehistoric Era
These characters appeared in "Ugh". They have the physical characteristics of a Neanderthal, and have one protuberant, square tooth. They all seem to have a tendency to refer to themselves in third person:
SpongeGar - SpongeBob's ancestor, who looks like SpongeBob but with somewhat different clothes and with a five o'clock shadow. He has one buck tooth and hairy hands.
Gary - Gary's ancestor, before Leech. SpongeGar's pet. About fifty times the size of modern Gary. It is believed that his name is Tobanga Gary, but Tobanga is a BC-esque form of "come on". As heard in Ugh "Tobanga Gary! (Gary does not come) GARY! Tobanga!"
Patar - Patrick's ancestor. He has a large jaw and Neanderthal-like brow.
Squog - Squidward's ancestor, before Squidly. He hates SpongeGar and Patar and takes advantage of them.
Krab - A possible ancestor of Mr. Krabs, before King Krabs. They run around saying "Money, money, money." One was killed when SpongeGar squashed it. Later in the episode, various of them appear when a rock is lifted.
Prehistoric Era Animals/creatures
Alarm Fish: Several large prehistoric fish that wakes up SpongeGar in the beginning of "Ugh" They make the same loud alarm as his descendant's clock makes. They look like the still living Prehistoric fish, the Coelacanth, excluding the large size. They only appear in the Advanced Prehistoric Era along with SpongeGar & others in Ugh.
Primitive Jellyfish: Although they do not appear in SB-129, Ugh, or anywhere else in the SpongeBob Media, however, a smaller-than-normal pink jellyfish made a short appearance in SB-129, in which Squidward goes back in time and invents jellyfishing to Primitive SpongeBob and Patrick (because, they will not stop torturing themselves with the jellyfish). This could be the earliest jellyfish discovery in the series, but earlier when Squidward first goes to the past, an ancient shellfish that looks like the jellyfish swims in the distance for a short time. This could be the True ancestor of the jellyfish. It could have evolved in to the present day jellyfish, but it's uncertain. The early (Shellfish) jellyfish looks very close to a true extinct shellfish, the Ammonite. The Critter appears in the first scenes of prehistoric Bikini Bottom in SB-129. It also appears to the beginning of Ugh.
Squidly - Squidward's 7th great grandfather. King Krabs' court jester, who curses his 7th great grandson to never be able to play the clarinet properly.
King Krabs - Mr. Krabs' and Pearl's ancestor, the king of Bikini Bottomshire.
Princess Pearl - Mr. Krabs' and Pearl's ancestor, the daughter of King Krabs. She was taken to Planktonamore's castle until Patrick, SpongeBob, Medieval Sandy, and Squidly rescue her.
Lord Planktonamor - Plankton's ancestor, an evil wizard. He is the rival of King Krabs.
The Dark Knight - An ancestor of Sandy's. Originally a servant of the evil Planktonomor, she turns good after being spared by SpongeBob after defeat. Unlike her descendant, she does not need an air helmet to survive underwater; no explanation for this ability is ever given, but considering Planktonamor's magic, this ability could be magical. She is referred to as Medieval Sandy. Played by SpongeBob.
Karen - A crystal ball similar to the recent day Karen. It is common misconception to believe current-day Karen is her ancestor, but as this Karen is a crystal ball, and current day Karen is a Security computer (the security feature was found out in "Friend or Foe") they could not be ancestors, and as she was Planktonamor's wife, it could be that only King Krabs and Princess Pearl are the ancestors.
Sluggo the Leech - Gary's ancestor, a leech that is only shown in one scene, without a shell and sharp teeth.
Dragon Jellyfish - A giant, jellyfish-like monster with ten long tentacles, a pink/purplish red body, a long snake-like tail with a spade on it and sharp dorsal fins like sharks. He is indestructible and able to shoot a fiery, electrical lava-like substance. He enjoys eating Krabby Patties.
Mid 20th century
Mr. Stinky - A wealthy fish who owned the only eating establishment in Bikini Bottom that served burgers before Mr. Krabs and Plankton came along and during their childhood. Seen in "Friend or Foe?". Voiced by Thomas F. Wilson.
Old Man Jenkins - Mr. Krabs' neighbor who died after eating a contaminated burger. He could be a relative to the modern Old Man Jenkins and Farmer/Parasol/ and Cannonball Jenkins.
Johnny & other classmates - Krabs and Plankton's classmates in Elementary School.
Dame Mackerel - A fish from the English Channel. Has delicate skin that she cannot get into the sun.
Fish In Baggy Clothes - A fish that got Mr. Krabs's Clothes.
Leonard - A blue anchovy with a red shirt. He has a lot of twin brothers, Petro and Ryan being two of them. He is SpongeBob's Acquaintance.
Petro - A blue anchovy with a red shirt. He has a lot of twin brothers, Leonard and Ryan being two of them.
Ryan - A blue anchovy with a red shirt. He has a lot of twin brothers, Leonard and Petro being two of them.
Residents of Waverly Hills
Carlton Ritts - A fish that lives in a golden mansion. He has a tree that grows golden coconuts. His name spoofs Ritz Carlton
Cowfish Craig - A cowfish that lives in a shack. He is a friend of Sandy.
Battle for Bikini Bottom
Robo-Sandy - A giant robot that looks like Sandy; Patrick thought it was a giraffe. It served as the first boss in the game. SpongeBob and Patrick managed to defeat the Robo-Sandy by pressing the button of "BOOM."
Robo-Patrick - A giant robot that looks like Patrick, it has ice breath and a giant ice cream cone made of hot goo. It served as the second boss in the game. Spongebob and Sandy managed to destroy the Robo-Patrick by kicking the robot's back with "Kick Me Here!" (although that Spongebob thinking that may be a "self-destruct") and rescue Squidward.
Robo-SpongeBob - A giant robot that looks like SpongeBob, it's worse than the Patrick and Sandy Robots combined. It served as the third and final boss in the game. Spongebob has managed to defeat Robo-Spongebob by destroying nine glowing-light. However, Robo-Plankton has revived the robot by giving him a big muscles. Later, Robo-Spongebob was finally destroyed when Spongebob has destroy all the fuses inside of it.
Robo-Plankton - A robot that looks like Plankton, he's the main villain of the game.
Robo-Squidward - A robot that looks like Squidward, he only appears in the game boy advance version of the game. It's worse than SpongeBob and Plankton robots combined.
Rick and Dale - Two announcers for the racing levels.
Starfish Man - Patrick's alter ego in the game. His arch enemy is Dreaded Patrick. And he defeated the Giant Plankton.
Dreaded Patrick - Starfish Man/Tuxedo Patrick's arch enemy. Even though he was able to defeat Starfish Man by sending him into space, Dreaded Patrick was caught by a ring-shaped piece of which falls to Earth which trapping him.
Phone Guy - Some guy who calls Starfish Man to give him advice on how to save Bikini Bottom
and defeat Dreaded Patrick.
Chief and his "pretty, pretty" wife - A chief who runs a village inside an Alaskan Bull Worm, his wife is an ironing board.
Villagers - Villagers who live inside the Alaskan Bull Worm.
Patty U.F.O. - A U.F.O. shaped like a Krabby Patty. However, Starfish Man was finally destroying the Patty U.F.O. in space before Starfish Man goes back to the Bikini Bottom.
Aliens - Aliens who help Patrick in the space level.
Giant Plankton - Plankton's alter ego in the game. He is Starfish Man/Pirate Patrick's arch enemy. Later, during the fight against Starfish Man, he was finally defeated Giant Plankton by shrinking him using Shrinkifier Ray, causing Plankton reverted back to normal size.
Giant Krabby Patty - The main antagonist of the game.
Bus Robot - a robotic servant that gives advice and compliments on accomplishing tasks and after someone finishes a song. He looks like a cylindrical computer on wheels and has a hologram on the top of his computer that reveals a blue amulet-shaped holo-screen when needed.
Atlantians - L.R.H. isn't the only one that lives in Atlantis. Normal Atlantians live there, too. The only known of the jobs they do are painters, scientists and workers at the Atlantian Mint (no longer in service).
Princess Mindy - King Neptune's mermaid daughter, she urges her father to rule with compassion. Her voice was provided by Scarlett Johansson. Mindy the Mermaid is very optimistic. She asked her dad (King Neptune) to stop being so selfish. A spoof of Ariel who is King Triton's daughter in The Little Mermaid. Patrick Star has a crush on Mindy.
Cyclops - The evil diver who took SpongeBob and Patrick to a gift shop to sell them as novelties.
David Hasselhoff - The actor from Baywatch. Helps SpongeBob and Patrick make it back to Bikini Bottom in time in the Movie.
Dennis The Hitman - The cold blooded predator hired by Plankton to get rid of SpongeBob and Patrick. The license plate on his motorcycle reads "I-KILL-U" and on the sole of his boot it says "Your Head Here." Has Dennis stiched on back of leather jacket. He is tough enough to force a mustache to grow upon himself. Voiced by Alec Baldwin, but loosely based on Dennis Hopper's character from Easy Rider.
Goofy Goober - A large goofy sea peanut, and mascot of "Goofy Goober's Ice Cream Party Boat" where SpongeBob drowns his sorrows in after failing to get the manager's job at The Krusty Krab 2. "Goofy Goober's" is a spoof of "Chuck E. Cheese's" and Goober brand combination peanut butter and jelly stripes. A Goofy Goober back scatcher was seen in the episode Chimps Ahoy.
"The Bubble-Blowing Double Baby" - Two brown conjoined twins seen in the Thug Tug. They were beaten up after singing the "Goofy Goober Theme Song".
Ice-cream lady - Actually a bump on a monster's (actually a frogfish) tongue disguised to look like an old lady. The monster uses her to lure unsuspecting prey. SpongeBob got his hands stuck on a "fake" ice cream bowl and was nearly devoured by the beast. The monster also has a cat-shaped bump as well. Her voice was provided by Sirena Irwin.
Royal Crown Polisher - Polishes Neptune's crown. He was almost sentenced to 20 years in the Dungeon for touching Neptune's crown, but was saved by Mindy.
Squire - Neptune's Squire
Goofy Goober Clock - Clock that presents the Goofy Goober Peanut guy
Waiter - Waiter at the Goofy Goober. Does not like his job.
Clay - The guy who sold Neptune's crown to Shell City. His voice is heard on Mr. Krab's answering machine. Actually Sheldon J. Plankton in disguise.
Floyd and Lloyd - Gas station employees who insulted SpongeBob, Patrick, and Dennis.
Trench Monsters - Live in the giant trench that SpongeBob and Patrick had to cross in the Movie. Tried to eat SpongeBob and Patrick until they proved their "manliness", later followed SpongeBob and Patrick, but later got offended at SpongeBob's remark about "hideous monsters".