Horror heads, this one’s on the house. Mexico Macabro San Miguel kicks off a run of free, in-person screenings at Casa El Nigromante, starting Tuesday, Oct. 28, at 5 pm with El Hombre Búfalo. The program is part of Macabro’s nationwide tour, which has landed in five states and will continue in Guanajuato through early November. Expect contemporary Mexican genre films in a historic venue at the heart of San Miguel’s cultural district—no tickets, s…