He is the supposed uncle of Rosalita.
Miguel was a cattle rancher in Perfection Valley, appearing in both the first and third films. His last name has never been given, but it may be Pedilla, as Juan is his ancestor. He escaped the first Graboid attack in 1990 and remained in Perfection until the end of his days. An Ass Blaster killed him in 2001, making him the only character appearing in more than one Tremors installment to be killed off. Miguel was Catholic, as evidenced in the fact that he wore rosary beads and a Christian cross around his neck. When he died, Burt removed the rosary beads to later give to Miguel's relatives, which Rosalita Sanchez claimed to be.
Miguel didn’t appear to have much formal education, but he was not altogether unintelligent, as he was a source of ideas for his friends. He originated the idea of using a machine as a decoy for Graboids (he thought of using Walter’s small tractor, while Earl improved on this idea using remote-controlled vehicles). He mentioned once having an albino goat who never gave birth, which helped his friends realize that the same may be true for El Blanco, explaining why it never produced any Shriekers (realistically, however, this is a scientifically inaccurate explanation but it could be that the two genes are linked for Graboids).
He was split from the group, and the Ass Blaster went after him. The others shot at it, but it kept going for him, he was going to shoot it with his shotgun, but it flew into him, knocking him off the cliff.
It dropped dead on a fence close by to him. He was last seen lying on the ground covered in blood, where Burt took his rosary, which he would later give it to Rosalita.