Watch Julian Casablancas Crash Arcade Fire’s Lollapalooza Argentina Set

Arcade Fire’s performance at Lollapalooza Argentina last night was interrupted by a rather special stage crasher in the form of The Strokes’ frontman Julian Casablancas. Just as the band were launching into their opening song, “Normal Person,” Win Butler realized someone else on stage was wearing his giant bobble-head mask. See what happens in the video above—Butler notices the impostor around the 1:20 mark.