- SpongeBob SquarePants
- Gary the Snail
- Patrick Star
- Squidward Tentacles
- SWAT team
- HAZMAT Unit (debut)
- Old Man Jenkins
- Peterson Nat Tucker
- Debbie Rechid
- Dennis (citizen)
- Eugene H. Krabs
- Norma Rechid
- Norma's daughter
- Timmy (child)
- Martha Doris Smith
- Incidental 60
- Harold Bill Reginald Scott
- Billy (lime fish)
- Health inspector (debut)
- Shelley (cameo)
- King Neptune (mentioned)
SpongeBob is asleep, and Gary has no food, so Gary wakes up SpongeBob. SpongeBob attempts to feed Gary some All Organic Nature's Science Snail Food, but the food is disgusting to Gary. Instead, Gary would rather eat some contagious sea fungus on the floor, which SpongeBob considers very rude. SpongeBob tries to clean up the ick, but gets it on himself. He tries to clean it off, but it only spreads. He also tries not to scratch it because it is itchy, yet he still itches.
At the Krusty Krab, he flicks off some contagious sea fungus on his nose, but it grows on the wall and grows back and bigger on him. He tries scraping it off his arm into the trash, but the same thing happens. Squidward sees SpongeBob in his state and calls the SWAT team. It is claimed that SpongeBob has the most severe case of ick yet. When the team is carrying SpongeBob away in a cage, some contagious sea fungus flies off of him and lands on Squidward's head. After Squidward itches it, when giving a Krabby Patty to Old Man Jenkins, it gets onto him. Meanwhile, the SWAT team has SpongeBob quarantined in his house with a bubble around him with the contagious sea fungus having taken a turn for the worse.Patrick comes in and does idiotic things that could pop SpongeBob's bubble before SpongeBob has him stop. The two then partake in a game of Pirate Wrestling, that ends with Patrick destroying the bubble, which SpongeBob points out to him. Afterwards, Patrick blows another bubble around SpongeBob. Back at the Krusty Krab, the contagious sea fungus is spreading like crazy. Squidward unknowingly spreads it all over the food Mr. Krabs is cooking, and the customers get infected. After Squidward sees he is infected, he announces this and a mob forms to attack him. Mr. Krabs (who is infected too) stops it and defends his restaurant to a health inspector snaps at Mr. Krabs for thinking everyone was healthy.
However, SpongeBob arrives in his bubble, having taken another turn for the worse. The health inspector points this out and instigates everyone to riot as Mr. Krabs blames Squidward who shifts it to SpongeBob since he technically started it. Everyone prepares to attack SpongeBob for spreading the contagious sea fungus as SpongeBob cries icky tears in his bubble. From outside, Gary sees everything. SpongeBob notices everyone attacking is spreading the ick and warns them but its too late and the ick gets on everybody in the Krusty Krab when the bubble pops, releasing a huge amount of fungus, covering many areas of the Krusty Krab.
Gary then arrives licking the contagious sea fungus off of Mr. Krabs, as SpongeBob criticizes him until Mr. Krabs explains to SpongeBob that Gary is supposed to eat the fungus since he is a bottom feeder and that's their job. Indeed, Gary quickly eats the fungus off Squidward. Seeing this, the customers all beg for Gary to help them until Mr. Krabs comes up with an easy solution. The episode ends with Gary "de-icking" the Bikini Bottomites, by simply eating all the ick off their bodies, for $5.00 to Mr. Krabs' profit.
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
‣ Happy Sponge Chase Vibes - Nicolas Carr [title card]
‣ Pacific Romance - Jan Rap [opening]
‣ ? [drum roll]
‣ Hawaiian Party - Jan Rap, Peter Smid [organic snail food]
‣ Steel Sting (c) - Jeremy Wakefield ["Oh, company!"]
‣ Goofy Conversation - Nicolas Carr, Barry Anthony [green fungus on SpongeBob's head]
‣ Housewives Choice - Harry Bluestone, Emil Cadkin [SpongeBob taking a shower]
‣ The Jitters - Raymond C. Jones ["ITCH!!!"]
‣ The Tip Top Polka/The Cliff Polka - Chelmsford Folk Band [at the Krusty Krab]
‣ Graveyard - Johnny Pearson [fungus grows on SpongeBob's arms]
‣ The Tip Top Polka/The Cliff Polka - Chelmsford Folk Band [SpongeBob puts on rubber gloves]
‣ Drama Link (d) - Hubert Clifford [SpongeBob itching]
‣ Tomfoolery - David Snell ["Oh, hi, Squidward."]
‣ Drama Link (f) - Hubert Clifford [Squidward screams]
‣ Dramatic Cue (e) - Ronald Hanmer ["Help me..."]
‣ Command Post 1 - Harry Bluestone, Emil Cadkin [Squidward calls SWAT team]
‣ The Escape - John Scott [SpongeBob put in a cage]
‣ House of Horror - W. Merrick Farran [Squidward gets infected]
‣ Keel Row - Brian Peters ["Here's your change, sir."]
‣ Orchestrated Devices C - Raymond C. Jones ["What was that?"]
‣ Twilight Zone - Harry Bluestone, Emil Cadkin [SpongeBob in a protective bubble]
‣ Lonely Stranger - Laurie Johnson [SpongeBob breathing heavily]
‣ Gator - Steve Belfer [Patrick enters]
‣ Harp Ding - Nicolas Carr ["I've got an idea!"]
‣ Mission Improbable - Nicolas Carr, Barry Anthony [Patrick blows another bubble]
‣ Lap Steel - Nicolas Carr ["Patrick, you're a genius!"]
‣ The Rake Hornpipe - Robert Alexander White [Squidward spreads fungus to customers]
‣ Wild Eyes - Ronald Hanmer [Squidward screams]
‣ Orchestrated Devices B - Raymond Jones [Angry mob forms around Squidward]
‣ The Dreadnought Tea Clipper (b) - Tim Laycock, Robert Alexander White ["What's all the commotion about?"]
‣ Death of the Alien 1 [#38] - Harry Bluestone, Emil Cadkin [SpongeBob returns]
‣ Rescue - Cecil Milner ["Who's with me?"]
‣ Farewell to the Islands - Kapono Beamer [Gary slithers into dumpster]
‣ Rescue - Cecil Milner [everyone attacks SpongeBob]
‣ Dramatic Impact 6 - Ivor Slaney [SpongeBob's bubble bursts]
‣ Chief Taravana - Kapono Beamer [Gary eating fungus]
‣ Nostalgic Hawaii - George de Fretes, Jan Rap [ending]
- This episode is available on the Season 5 Volume 1, Complete Fifth Season, Friend or Foe?, and First 100 Episodes DVDs.
- Although this episode premiered in 2007, it was made in 2006 according to the credits.
- This episode aired in Germany on Thursday, May 17, 2007, before it aired in the United States.
- This episode was available on the Friend or Foe? and Season 5 Volume 1 DVDs, released earlier in 2007, before it aired on American television.
- This episode was paired up with "Le Big Switch" when it first aired in the United States.
- The title card background is similar to the one for "Sandy's Rocket," but it has a purple background instead of a red one.
- The ick is an actual disease that affects fish.
- No one seems to notice the ick on Squidward or the Krabby Patties until Squidward finds out he got infected.
- Since SpongeBob owns Gary, he doesn't need to pay Mr. Krabs to have Gary remove his ick.
- This is the only season 5 episode in which Gary plays a major role.
- This was Richard Pursel's first episode as a writer.
- This is the last episode to play the APM track "Nostalgic Hawaii."
- This episode premiered on Ian McShane's 65th birthday and one year after "Once Bitten" premiered.
- The episode's title comes the band Incubus's 1995 debut album, Fungus Amongus.
- The way SpongeBob's house is covered in a plastic bag with police tape and barbed wire around it is similar to the movie E.T. the Extra-Terrestrial.
- In the beginning of this episode, the windows outside of SpongeBob's house are facing backwards; in this episode, the low window is on the left while the higher one is on the right. In most others, the high window is on the left and the low window is one the right.
- When Old Man Jenkins leaves after getting his change, Squidward Tentacles calls himself "Mr. Squidward" even though Squidward is his first name. A more proper way of saying this would be "Mr. Tentacles."
- When SpongeBob wakes up in his quarantine house, he sees two silhouettes of hazmat fish with "eye" holes. In the next shot, the workers have a singular glass visor.
- When the Bikini Bottomites jump on SpongeBob's bubble and on the scene when the bubble explodes, Patrick is not seen by the doors, in the next scene he is seen getting "the ick" all over him.
- On the DVD releases, in the scene when Gary is eating the ick off of Mr. Krabs, SpongeBob says, "Gary the Snail." However, the captions incorrectly translate, "Gary D. Snail."
- In the Netflix version, the audio is a bit slow.