Thierry Mugler chose the catwalk as the venue for his 20th anniversary party at the Cirque d’Hiver. That it was OTT was given: Mugler was a showman who went on to design costumes for the movies and, yes, the circus. The “scalpel-cut and aerodynamic details” that Vogue once credited him with were evident in the collection’s tailoring, but the show was memorable more for its perf...