Throughout the series, the main characters have acquired alter-egos (normally only lasting one episode).
SpongeBob SquarePants
SpongeBob as the open window maniac
SpongeBob as Fry Boy
SpongeBob as Flabby Patty Cook
SpongeBob as Sponge of Mystery
- Idiot Boy - "Whatever Happened To SpongeBob?"
- JellyBob - "Nature Pants"
- Open window maniac -"Hall Monitor"
- SpongeBob ScaredyPants - "Scaredy Pants"
- The Flying Dutchman - "Scaredy Pants"
- New SpongeBob - "Breath of Fresh Squidward"
- Sponge of Mystery - Mermaid Man and Barnacle Boy II
- Patrick - "Big Pink Loser"
- Man Sponge - "Mermaid Man and Barnacle Boy III"
- The Quickster - "Mermaid Man and Barnacle Boy V"
- Krabby Patty burglar - "Krabby Land"
- The Bird Man of Bikini Bottom - "The Sponge Who Could Fly"
- SquidBob TentaclePants - "SquidBob TentaclePants"
- TardyPants - "New Digs"
- Short Order Boy - "Krusty Krushers"
- The Yellow Avenger - The Yellow Avenger (video game)
- Robert - "Patrick SmartPants"
- CheeseHead BrownPants - "What Ever Happened to SpongeBob?"
- Fry Boy - "Mermaid Man vs. SpongeBob"
- SpongeBob RoundPants - "To SquarePants or Not to SquarePants"
- Normal SpongeBob - "Not Normal"
- Scary Mustache Guy - "The Pink Purloiner"
- Invincibubble - The SpongeBob Movie: Sponge Out of Water
- SpongeRobert- "SpongeBob LongPants"
- Flabby Patty Cook - "The Other Patty"
- Elf SpongeBob - Christmas with Krabby Klaws
- Mermaid Pants - "Mermaid Pants" and "Man Ray Returns"
- Abrasive SpongeBob - "The Abrasive Side"
- Sir SpongeBob - "Dunces and Dragons"
- SpongeBob WormPants - "House Worming"
- Le Squish - "Demolition Doofus"
- Sponge the Horse - "Pat the Horse"
- Chumta Claus - "Plankton's Old Chum"
Patrick Star
Patricia
- Tubby - "No Weenies Allowed"
- Rick - "The Fry Cook Games"
- SpongeBob - "Big Pink Loser"
- Boy Patrick - "Mermaid Man and Barnacle Boy III"
- The Elastic Waistband - "Mermaid Man and Barnacle Boy V"
- Sir Patrick - "Dunces and Dragons"
- Patrick SmartPants - "Patrick SmartPants"
- Patricia - "That's No Lady"
- Mr. Dr. Prof. Patrick - "Chimps Ahoy"
- New Patrick - "Breath of Fresh Squidward"
- Starfishman - Creature from the Krusty Krab
- King Patrick - "Rule of Dumb"
- Pink Patty - "Krusty Krushers"
- Patrick-Man - "Patrick-Man!"
- Mr. Superawesomeness - The SpongeBob Movie: Sponge Out of Water
- Patrick (snail) - "Sanctuary!"
- Barnacle Star - "Mermaid Pants," "Man Ray Returns," and "Appointment TV"
- Pat the Horse - "Pat the Horse"
- Pat the Crab - "Pat the Horse"
- Wonderful Guy - The Evil That Mendu!
- Old Man Patrick - "Old Man Patrick"
- Patnocchio - "Patnocchio"
Squidward Tentacles
Squidward as Mr. Handsome
- Jerk who reads diary/Diary thief - "Little Yellow Book"
- Squidward's ghost - "Squidward the Unfriendly Ghost"
- The Flying Dutchman - "Scaredy Pants"
- Wolfgang Amadeus Tentacles - "Sleepy Time"
- Santa Claus - "Christmas Who?"
- Jen - "As Seen on TV"
- Captain Magma - "Mermaid Man and Barnacle Boy V"
- SquidBob TentaclePants - "SquidBob TentaclePants"
- Smelly - "The Thing"
- New Squidward - Breath of Fresh Squidward
- Handsome Squidward - "The Two Faces of Squidward"
- Normal Squidward - "Not Normal"
- Gerhard Fishtrap - "Sold!"
- Hedvig Fishtrap - Sold!
- Sour Note - The SpongeBob Movie: Sponge Out of Water
- Doctor Negative - "Mermaid Pants" and "Appointment TV"
- King of Sports - "Sportz?
- Squid the Horse - "Pat the Horse"
- Bunny Squidward - "Bunny Hunt"
Eugene H. Krabs
Captain Krabs
- Captain Krabs - "Arrgh!" and "Grandpappy the Pirate"
- Harold Flower - "Born Again Krabs"
- Krabby the Clown/Cheapy the Cheapskate - "Krabby Land"
- Sir Pinch-a-Lot - The SpongeBob Movie: Sponge Out of Water
- Captain Tightwad - "Mermaid Pants" and "Appointment TV"
- Super Tightwad - "And Krabs Saves the Day"
- Armor Abs Krabs - "Shell of a Man"
- Sir Crumple O'Wrapper - "Chum Fricassee"
Sheldon J. Plankton
Plankton as Mr. Plankton
- The Amazing Plankton - "Culture Shock"
- Mr. Plankton - "The Algae's Always Greener"
- Dr. Peter Lankton - "Fear of a Krabby Patty"
- Professor Plankton - "Mermaid Man vs. SpongeBob"
- Plankton SquarePants - "The Inside Job"
- Plankton Star - "The Inside Job"
- Great-grammyma - "Gramma's Secret Recipe"
- Sheldon R. Shellcleaner/Gary the Snail - "Shellback Shenanigans"
- Planktonella - "Eek, an Urchin!"
- Plank-Ton - The SpongeBob Movie: Sponge Out of Water
- Cashina - "Married to Money"
- Genie the Wish Granter - "Spin the Bottle"
- Ray Ray - "Grandmum's the Word"
- Conscience - "Patnocchio"
- Man Ray - "Appointment TV"
Karen Plankton
- Racing worm - "Frozen Face-Off"
- Ms. Karen - "Salsa Imbecilicus"
- Karen the Cat - "The Legend of Boo-Kini Bottom"
- Karen the Computer Fairy - "Patnocchio"
- Mr. Krabs - "Girls' Night Out"
Sandy Cheeks
- Goldfish - "Scaredy Pants"
- Miss Appear - "Mermaid Man and Barnacle Boy V" and "Appointment TV"
- Mr. Pavlovi - "The Fish Bowl"
- The Rodent - The SpongeBob Movie: Sponge Out of Water
- Ms. Cheeks - "Salsa Imbecilicus"
- Dr. Franken-Cheeks - "The Legend of Boo-Kini Bottom"
- Mr. Krabs - "Girls' Night Out"
- Super Sandy - "Squirrel Jelly"
Mrs. Puff
- Witch - "Scaredy Pants"
- Mrs. Pop - "Demolition Doofus"
- The Huff - "Demolition Doofus"
- Bote Thief - "Patrick-Man!"
- Atomic Flounder - "Appointment TV"
- Mr. Krabs - "Girls' Night Out"
- Norton - "Girls' Night Out"
- Ghost - SpongeBob Game Station
Pearl Krabs
Pearl Krabs aka Amy
- Bride of Frankenstein - "Scaredy Pants"
- Witch - The Big Halloween Scare
- Amy - "As Seen on TV"
- The Invisible Boatmobile - "Mermaid Man & Barnacle Boy VI: The Motion Picture"
- Mad Hatter - SpongeBob Game Station
Gary the Snail
- Dirty Bubble - "Appointment TV"
Patchy the Pirate
- Patchy the Caveman - "Ugh"
- Pagey the Pirate - "Truth or Square"
Potty the Parrot
- Robot - "Ugh"
Mermaid Man
- Ernie - "Mermaid Man Begins"
Barnacle Boy
Barnacle Man (center)
- Barnacle Man - "Mermaid Man and Barnacle Boy V"
Larry the Lobster
- Mermaid Man - "Appointment TV"
SpongeBot SteelPants
Robo-SpongeBob MusclePants.
Globulous Maximus
SpongeGlob
Frogfish
This list is incomplete, but you can help Encyclopedia SpongeBobia by expanding it.