Nightclubs in Rio de Janeiro are being plagued by a re-emergence of “pitboy” gangs that originally surfaced in the late 1990s. Pitboys are named after aggressive pitbull dogs and they intimidate and attack patrons of nightclubs and bars in the popular Copacabana-Ipanema-Leblon areas. They are reportedly martial arts aficionados, from the middle class, with shaved heads and sleeveless t-shirts to show off their tattoos. Some commentators say their aggressive behavior is fueled by steroids. Incidents have been occurring almost nightly and nightclubs are raising their cover charges, denying entry to unaccompanied men, adding security personnel and making contact with local military police who patrol the area. Incidents usually occur in the early morning hours when bars are closing, and the thugs are indiscriminate, attacking old, young, men, women, locals or foreigners.