[zorrophreak]

Actually it was secretly developed by the Aryan Brotherhood to show allegiance to their race (by saluting the fuhrer) and pretending to be blinded by his glory. It translates to "Destroy All Blacks" and the full name, Dab on Em, translates to "Destroy All Blacks, Oppress Non-Whites, Eliminate Minorities). It is an extremely racially insensitive gesture that white supremacists tricked into going into Black Culture during 2016.