Moco is the ruthless drug lord in El Mariachi. He is portrayed by Peter Marquardt.

In El Mariachi Moco tells his hitmen to find a ruthless criminal, and enemy, named Azul. Moco gives the simple description that Azul wears black and carries a guitar case, which is full of guns and knives, and his men mistake a mariachi as Azul, as he fits the desciption.

Mariachi kills several of Moco's men, in self defense. He is captured by one of the men, and beaten, then taken to Moco's ranch. Moco tells the men it's not Azul, and they let him go. But he'll come back...

Mariachi and Domino, who is his employer, start to have an affair. Moco wants to win Dominos love, but he hasn't. One night he calls Domino, when Mariachi is there, and she hangs up.

Suddenly Azul comes into Domino's bar and asks her to drive him to Moco's ranch, which she does. When they get there, Azul holds a gun to Domino and tells Moco to give him the money that he didn't get, or she dies. Mariachi, seeing Domino isn't there, jumps on a motorcycle and drives to the ranch. But he is too late...

Domino AND Azul are dead, and Moco is laughing. He shoots Mariachi in the hand, for revenge, so he can't play the guitar anymore. With his other hand, Mariachi shoots Moco, killing him, and then gets on the motorcycle and leaves the town.