A wannabe Bronx rapper horrifically beat a cat to death in ritualistic sacrifice to Satan and posted about it on social media to promote his small-time music career, police and sources said. Fordham North resident David Mosley, 26 — who goes by the alias Church of Ububal — was arrested Thursday for killing the kitty, law enforcement sources said, after boasting in a YouTube rant that he was inspired by a Norwegian black metal band whose bassist “literally murdered” another member of his band, an apparent reference to the band Mayhem.