Nicki Minaj is always a pleasure to watch – goofy, surreal, stylish, impeccable on the mic. She has upstaged some of the biggest stars in rap, but in this clip from last night's Billboard Music Awards, she's the one getting eclipsed. After Nicki and her crew deliver a fine rendition of "Superbass," Britney Spears pops up for a quick run through her latest hit "Till the World Ends," and the whole room goes nuts. To some extent, the excitement comes down to "OMG BRITNEY!," but it's mostly about the intensity of the song's massive "oh oh oh oh oh" hook. Not even the mighty Minaj can stand up to that kind of pop power.