The band's legion of fans, aka Juggalos, are as infamous as the band, growing so massive that ICP hosts an annual "Gathering of the Juggalos" that draws thousands to indulge in a wide range of activities including performances by artists on the band's Psychopathic Records label, celerity hosts, wet T-shirt contests, a "Miss Juggalette" pageant and "Juggalo Championship Wrestling."

None less than the Federal Bureau of Investigation took notice of ICP and the Juggalos, and in 2011 issued the "National Gang Threat Assessment: Emerging Trends,"a report that classified Juggalos as a "loosely organized hybrid gang," with warnings that they'd begun expanding across the country and were known to "exhibit gang-like behavior and engage in criminal activity and violence."

While the initial report generated plenty of headlines and jokes regarding ICP and their fans, the band found the gang classification no laughing matter, and this week filed a lawsuit against the F.B.I. and the American Justice Department for the "unwarranted and unlawful decision" to tag its followers as criminals and subsequently treating them as such.

"Among the supporters of almost any group�whether it be a band, sports team, university, political organization or religion�there will be some people who violate the law," reads the suit. "However, it is wrong to designate the entire group of supporters as a criminal gang based on the acts of a few. Unfortunately, that is exactly what happened here."

"The FBI had the impact they wanted: they scared people away from attending concerts and from affiliating together for the purpose of listening to music," said lawyer Saura Sahu, who's working with the ACLU of Michigan on the case to Rolling Stone, adding that the increased scrutiny resulted in a declined attendance at this year's Gathering of the Juggalos. The group also said they were forced to cancel a 2012 show in Royal Oak, MI, after local police cited the F.B.I.'s new gang classification of Juggalos.