- Incidental 48
- Evelyn Annette
- Harold Bill Reginald Scott
- Squidward Tentacles
- Incidental 104
- Nathiel Waters (normal; purple)
- Tina Fran
- SpongeBob SquarePants
- Sea slug (mentioned)
- Eugene H. Krabs
- Sheldon J. Plankton
- Frank the Red-Shirt-Wearing Fish
- Nancy Suzy Fish
- Vera Fishbowl
- Karen Plankton
- Betsy Krabs
- Frankie Billy
- Miss Rechid
- Jimmy Gus
- Jennifer Millie
- Old Man Jenkins
- Frank the Lifeguard
- Male judge
- Incidental 13
- Peterson Nat Tucker
- Perry (teal)
- Sheldon the Fish
- Shelly Fishbowl
- Susie Rechid
- Martha Smith
- Lion Fish (debut)
- Incidental 2
- Frank the Goldfish
- Incidental 47
- Patrick Star
- Gladiator (debut)
- Popeye fish (Blue)
- Monroe Timmy
- Norma Rechid
- Jellyfish (mentioned)
- Whale (mentioned)
Plankton decides to destroy the Chum Bucket and turns it into a coliseum, announcing to Bikini Bottom on a jumbotron that there will be free entertainment, promising guts, and glory available to everyone in now what is called the Chum Coliseum. The coliseum is a spoof of the Roman arena with its battles and gladiatorial games, complete with Plankton in the Emperor's chair and a toga. Soon, the Krusty Krab is devoid of its loyal customers, and Mr. Krabs and the crew go to the coliseum to find out what Plankton is up to. When they sit down, a giant lionfish is released and SpongeBob is excited about who will get mauled until he realizes the prisoner that will be going up against the lionfish is Patrick. To entice the lionfish into chasing Patrick, Plankton orders blood sausages to be placed around Patrick's throat. SpongeBob decides to help Patrick and turns into a gladiator, complete with armor and a chariot pulled by seahorses.
He soon catches up with Patrick and rescues him, but now the entertainment has turned into a chase scene that does not contain the blood and guts Plankton promises, even when Betsy Krabs wants to see "body parts." Meanwhile, Plankton is trying to sell chum to the crowd who are getting hungry waiting for the guts and glory. One of the spectators agrees to buy a chum stick but is angered when Plankton tells her it will be $10. She angrily asks why she should pay $10 when Krabby Patties are only a single buck, which the overhearing Mr. Krabs agrees to. Plankton angrily tells her "You can't get entertainment like this at the Krusty Krab!" and states that the fight will be off unless she pays $10. She agrees and immediately gets sick from eating the chum stick, while the rest of the crowd, having had enough, get up to go. Plankton traps all of the customers by blocking off all the exits when they try to leave. He claims to have waited 20 years to see the number of customers Mr. Krabs sees every day and demands everyone to sit back down and buy his chum. They sit back down grumbling and the entertainment continues.
Going back to SpongeBob and Patrick, SpongeBob discovers that the Lion Fish is chasing the blood sausages around Patrick's neck, not them, after witnessing the Lion Fish eat a sausage that was thrown on the ground. He throws the rest of the blood sausages and they land in a pile on Plankton. He freaks out, now realizing the Lion Fish is charging towards him. He quickly escapes out of a secret door he had placed in the coliseum, taunting the Sea Lion and calling it a "prissy feline." The Lion Fish smashes through the wall and chases Plankton who runs for his life. After Plankton's failed plans, the Krusty Krab is back in business, but Mr. Krabs has raised the price of a Krabby Patty from $1 to $10. When a customer complains about it, Mr. Krabs points to the Lion Fish and tells him he can talk it up with his new "financial advisor." The scared customer then complies and buys the patty.
Mr. Krabs, SpongeBob, Patrick, and Squidward laugh altogether and then leave rather awkwardly one by one. The episode ends with the lionfish roaring.
- Customers complaining about the food costing ten dollars instead of one dollar.
- As a result of their complaint, there are consequences if they don't pay ten dollars such as Plankton calling off the fight and Mr. Krabs telling Wobbles to speak to the "financial expert" which is the chained lion fish.
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
‣ Roman Legion - David Farnon [title card]
• How Much Chum Can a Sea Slug Chug Song - Nicolas Carr [SpongeBob singing]
• Steel Licks 8 - Jeremy Wakefield [SpongeBob dialing phone]
‣ Dramatic Impact 6 - Ivor Slaney ["Mr. Krabs, you gotta get out here!"]
‣ Dramatic Impact 5 - Ivor Slaney ["It's a code blue situation!"]
‣ Zelle 503 - Gerhard Trede [Chum Bucket demolished]
‣ Keel Row - Brian Peters ["Plankton's destroying the Chum Bucket?!"]
‣ Battle March Link (d) - Keith Mansfield [Chum Bucket replaced with coliseum]
‣ Ancient Fanfare [#51] - Harry Bluestone ["Greetings, citizens of Bikini Bottom!"]
‣ Ancient Fanfare [#51.04] - Harry Bluestone ["I vow to introduce to this fair city culture!"]
‣ Ancient Fanfare [#51.05] - Harry Bluestone ["I intend to enrich your lives culturally."]
‣ Fighting Legions - Gregor F. Narholz [everyone rushes in]
‣ Dramatic Impact 6 - Ivor Slaney [Plankton laughs evilly]
‣ Wooden Bear - Gil Flat, Tony Tape, Florian Voelxen ["Even though you're just a frigid machine, your circuits must be welling up with emotion."]
‣ Hawaiian Link (b) - Richard Myhill [Krabs and SpongeBob get up off the ground]
‣ Tripping Upstairs - Brian Peters ["Let's serve 'em up a burger they tell their grand-guppies about!"]
‣ Drama Link (e) - Hubert Clifford [Krusty Krab empty]
• Tension Bits - Nicolas Carr, Sage Guyton, Jeremy Wakefield [Krabs gets angry]
‣ Roman March - Robert Sharples ["Gentlemen, to the coliseum!"]
‣ The Tale of Ben Hur 1 - Gregor F. Narholz ["Patrick?!"]
‣ Mounting the Scaffold 1 - Gregor F. Narholz [sea lion roars at Patrick]
‣ Armed Attack 1 - Mladen Franko [sea lion chases Patrick]
‣ Entry of the Heroes D - Gregor F. Narholz [SpongeBob jumps into a chariot]
‣ Chariot Race - Helmuth Brandenburg [SpongeBob pulls Patrick into the chariot]
‣ Entry of the Heroes A - Gregor F. Narholz ["This is ridiculous!"]
• Plankton's Ballpark Organ - Nicolas Carr [Plankton selling chum]
• Steel Licks 1 - Jeremy Wakefield ["That was appalling!"]
‣ Mounting the Scaffold 1 - Gregor F. Narholz [Plankton traps everyone in the coliseum]
• Steel Sting - Jeremy Wakefield [they go back to their seats]
‣ Chariot Race - Helmuth Brandenburg [SpongeBob and Patrick still being chased]
• What's This - Nicolas Carr ["Huh?"]
‣ Chariot Race - Helmuth Brandenburg ["That's it, Patrick!"]
• Plankton's Ballpark Organ - Nicolas Carr [sausages land on Plankton]
‣ Armed Attack 1 - Mladen Franko [sea lion roars at Plankton]
• Grass Skirt Chase - Sage Guyton, Jeremy Wakefield [sea lion chases Plankton]
‣ The Tip Top Polka/The Cliff Polka - Chelmsford Folk Band [back at the Krusty Krab]
• Nude Sting - Nicolas Carr [Patrick's butt]
‣ The Tip Top Polka/The Cliff Polka - Chelmsford Folk Band [Krabs charges $10 for a Krabby Patty]
‣ Captain Lenoe's - The Folk Players [everyone stops laughing]
• Lap Steel - Nicolas Carr [ending]
- This episode is available on the Spongicus, Season 6 Volume 1, Complete Sixth Season, SpongeBob's Legendary Adventures, Kids Double Pack: Volume 6, The Ultimate SpongeBob Box Set, 3 DVD Value Pack Volume 2, The SpongeBob SquarePants Collection, The SpongeBob SquarePants 8 Season DVD Collection, Time Travel, Mighty Sporting of You, SpongeBob SquarePants Vol. 9, The Best 200 Episodes Ever, and Next 100 Episodes DVDs.
- "Spongicus" was ranked #76 during the SpongeBob's Top 100 event in the UK and Ireland from June 4-8, 2012.
- The title card for this episode is similar to that of "Artist Unknown."
- This is the first episode where chumsticks appear.
- The title card is a parody/reference to Ancient Greek text, but the "U" in Spongicus is not shaped like a "V" like it would have been back then.
- During the History of SpongeBob Marathon, This episode was paired with "Dear Vikings."
- This episode premiered on the same day as the 2008 Kids' Choice Awards.
- This is the fifth episode (along with the episode "Nautical Novice") to premiere on the same day as the Kids' Choice Awards. The first was "Help Wanted"/"Reef Blower"/"Tea at the Treedome" in 1999, the second was "Krabby Land"/"The Camping Episode" in 2004, the third was "Krusty Towers"/"Mrs. Puff, You're Fired" in 2006, and the fourth was "Born to Be Wild"/"Best Frenemies" in 2007.
- The episode first aired with "Nautical Novice," but was later paired up with "Suction Cup Symphony."
- On the Complete Sixth Season, Season 6 Volume 1 and The Next 100 Episodes DVDs, this is the first episode even though it is not the first episode in season 6.
- Angry Jack, whose name is revealed in the episode "Shell Shocked," can be seen in the audience of the coliseum.
- When SpongeBob gets in the chariot, his clothes transform into Roman gladiator armor.
- Like the sea bear from "The Camping Episode," the lionfish is portrayed as a fish with a predatory animal's head and claws on the tips of its pectoral fins.
- However, unlike sea bears, lionfish exist in real life, but they do not look anything like in the episode.
- Chumsticks come in two shapes: square and corndog-shaped.
- According to this episode, Krabby Patties only cost a dollar.
- According to this episode, the secret formula for Plankton's chum is whale blubber, jellyfish squeezings, seahorse snout, and just a sprinkle of anchor rust. That means Plankton's chum is different from common chum.
- In a much later episode, "Jailbreak!," Plankton uses an alternate way of creating chum.
- During the History of SpongeBob Marathon, it was paired up with "Dear Vikings."
- SpongeBob is shown eagerly waiting for a stranger to get mauled by the sea lion before he discovered it is Patrick, which is a rare time where he wants harm on someone.
- In airing order, this is the 200th episode segment.
- In this episode, Plankton says he has waited for 20 years to get the number of customers Mr. Krabs sees every day. However, in "Plankton's Army," it is the 25th anniversary of Plankton stealing the Krabby Patty secret formula.
- In Bahasa Indonesia version, the opening scene featuring Plankton destroying his Chum Bucket and replacing it with coliseum along with Betsy Krabs throwing a tomato in coliseum was omitted due to time constraints.
- On the May 13, 2015 airing, this episode was played with the audio a few seconds behind for the first few minutes. This was until the scene of the Colosseum started to fill up.
- The title "Spongicus" is a spoof of the infamous Roman gladiator Spartacus.
- The coliseum that Plankton made is similar to the Colosseum of Rome.
- The lionfish is a parody of the Nemean Lion from Greek mythology and a visual pun on real-life Lionfish.
- The lionfish also resembles Merlion, the national symbol of Singapore.
- When SpongeBob gasps while cleaning the window, one of his teeth flicker from white to yellow.
- At the beginning of the episode, SpongeBob warns Mr. Krabs about Plankton through a pay phone in the Krusty Krab. However, the payphone disappears in later scenes and is not seen for the rest of the episode.
- Patrick's toga is white, but in one scene, it turns green.
- When the people leave the Colosseum, they wind up in the area of the arena. Plankton is also in the arena when vending chumsticks. In reality, they could not go from the bleachers to the arena; corridors would lead from the bleachers to the outside of the Colosseum.
- Also, the chariot and the lionfish are not there.
- Patrick's lips turn pink, instead of black, towards the end of the episode.
- The cash register is not at the counter at the end of the episode when everyone is laughing around it.
- At the end of the episode when the lionfish roars and it shows the Krusty Krab, the clam sign is not there.
- Along with its sister episode "Suction Cup Symphony," there is no year or copyright information anywhere in the end credits.
- This is also the second episode with an error in the closing logos. The first is "Krusty Krab Training Video."
- After Plankton destroys the Chum Bucket, part of Mr. Krabs's shirt becomes transparent.
- ^ Airdate confirmed on Apple TV