SpongeBob is asleep, and Gary has no food, so Gary wakes up SpongeBob. SpongeBob attempts to feed Gary, but the food is disgusting to Gary. Instead, Gary would rather eat some contagious sea fungus on the floor, which SpongeBob considers 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. 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 pops SpongeBob's bubble, but blows another one around SpongeBob. Back at the Krusty Krab, the contagious sea fungus is spreading like crazy! It is all over the food, and the customers get infected. SpongeBob arrives in his bubble, having taken another turn for the worse. The health inspector snaps at Mr. Krabs for thinking everyone was healthy, and everyone prepares to attack SpongeBob for spreading the contagious sea fungus. SpongeBob cries icky tears that get on everybody in the Krusty Krab when the bubble pops. Gary then arrives licking the contagious sea fungus off of Mr. Krabs. The episode ends with Gary "de-icking" the Bikini Bottomites for $5.00 to Mr. Krabs' profit.
This is considered one of the worst episodes because of how disgusting the fungus was. On PIEGUYRULZ's video of "Every Season 5 episode reviewed, he called this the most appropriate episode to call it "ScumBob."