When it comes to horror, Broadway typically cedes turf to Hollywood, the occasional Martin McDonough play notwithstanding. There have been giant apes, operatic phantoms, and a misguided vampire or two without providing so much as a single genuine tingle. All of which makes the effort of Grey House so bold. A creepy mash-up of haunted house tropes, cabin in the woods traditions, ghosty kids, errant hatchets, screams, black-outs and the sort of Lynchian lounge music that drips with reverb and menace, Grey House hails from the playwright Levi Holloway and director Joe Mantello, with stars Laurie Metcalf, Tatiana Maslany, and Paul Sparks joined by ferociously talented quintet of child-to-adolescent actors.