Monster Massive was a Halloween-themed electronic music festival held annually on a weekend near Halloween at the Los Angeles Sports Arena in Los Angeles, California. Many of the attendees dressed in costume. The event was sponsored by Go Ventures. Monster Massive was host to some of the biggest names in electronic dance music, including Paul Van Dyk, Armin Van Buuren, Deep Dish, Hernan Cattaneo, Carl Cox, John Digweed, Sasha, Felix Da Housecat, Armand Van Helden and many others.