[Name] 'Joy Virus' [Source] The Amazing World of Gumball (The Joy) [Symptoms] 
Is an emotional-psychological virus that title protagonist father cause within first few hours by start from unexplained and uncontrolled mood swings on heavily happiness induced hallucinations, salvia and also coughing that recently mutated accidentally; Than the virus later seemly killed the first victims within after the first few hours and later come back as creepy happy zombie-like things dubbed "Huggers" by Miss Simian that attack the protagonist middle school.