A Sur Trece gang. Stands for Mexicanos Malditos Sureños 13.
(NOT related to MS 13)
A couple rivals: FUCK newhall 13, brown familia 13, & canyones 13!
BUSTER: Ey homie dont fuck with that Sureño
CHAPETE: Why dog?
BUSTER: Cus he's from Barrio M.M.S.
CHAPETE: Oh shit i heard they dont play games!
Man homie they cant touch us! We come from that big bad sur side gang, straight MMS GANG! All the south west, california to texas.