"Black hand of the Mexican MafiaNicknamed the ""black hand of death"" according to former gangster Rene Enriquez, this tattoo is an identifier for members of the Mexican Mafia. Enriquez told NPR in 2008 that the Mexican Mafia was one of the most influential gangs of California, having infiltrated nearly every prison in the state.  Photo: Bob Chamberlin, LA Times Via Getty Images"