Disco is one of those words that the senses respond to instantly with several very particular references: late 1960s or early ’70s New York City spring to mind. However, the world of Disco Pigs is a far cry from that, and disco assumptions are turned on their head. Enda Walsh’s play strips the term bare of its bright-lights, big-city ballroom connotations, throws a hefty dose of punk into the trunk, then turns off-road onto the aimless side of life. But it does so with deep, dark humor, wide-eyed invention and heaps of passion.