Mad Snail Disease
Mad Snail Disease
Type: Disease/Virus
Appearance: "Once Bitten"
List of objects

Mad Snail Disease (a parody of Mad Cow disease) is a mythological disease/virus that was believed that snails could be afflicted with. Patrick Star informed SpongeBob SquarePants and Squidward Tentacles of it's supposed existence, before everyone was informed by Dr. Gill Gilliam, who appeared to be the only one in Bikini Bottom who could confirm that the disease is a myth. The virus caused massive panic within the Bikini Bottom, as it was feared that a bloodborne (and later an airborne) outbreak had started in the town. MSD was believed to be a highly contagious virus that caused rage in snails and zombie-like symptoms in fish and other creatures. Leading to mass hysteria and destruction throughout the town as residents were 'infected' and believed they were flesh-craving zombies.

The 'Outbreak'

In the episode "Once Bitten," Squidward was bitten by Gary, and was 'infected' with the Mad Snail Disease. When Patrick sees Squidward getting bitten by Gary, he tells Squidward that Gary has "Mad Snail Disease." SpongeBob tries to take Gary to Snail Care, but Gary escapes and bites nearly every Bikini Bottomite, supposedly starting a rage-filled outbreak of MSD. As the last 'survivors' of the 'outbreak' watched in horror as the raging Gary bit SpongeBob, supposedly infecting him, Dr. Gill Gilliam tells the Bikini Bottom that Mad Snail Disease is just an old urban legend and simply doesn't exist. He reveals that Gary's rabies-like symptoms were simply caused by pain and irritation from a "little" splinter in his foot from Squidward's anti-snail defense. Gary wasn't infected and he didn't start an outbreak of anything except for mass hysteria. The only thing inlicting Gary was Grouchy Snailitis. Just as 'the infected' broke into the fortified Krusty Krab, Squidward continued to groan like a zombie. Admitting he was not, and that he was just groaning because he had to go to work. The other 'infected' presumably realized this too and order returned to the Bikini Bottom.


  • Ticklish ribs
  • Loss of balance
  • Blood shot eyes
  • Sore throat
  • Messy pants
  • Severely untrimmed toenails
  • Large rash
  • "Zombification"
  • It appears to cause symptoms similar to rabies. However, this seems to be exclusive to Snails such as Gary, who was the original source of the 'outbreak'.

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