With disco fever still at pandemic levels, Liars’ “Mr. Your on Fire Mr.” is just as relevant as upon its release on the then-Brooklyn-based band’s 2001 debut album, They Threw Us All in a Trench and Stuck a Monument on Top. The itinerant trio recently remixed the frenetic post-punk update, stretching “Mr.” to 19 minutes — more than seven and a half times the song’s original length. The occasion for this surprise treat? “We were approached by Hedi Slimane to reconfigure this track for the Saint Laurent Spring/Summer ’14 runway show,” the band explained on Facebook. “And by reconfigure we mean: Take the short original that was made in turn-of-the-millennia NYC, grab it by the throat, punch it in the face and kick it down the street until it reached a place we’d never imagined possible before.” Strut down the runway while streaming the resulting excellence below.