Justin Dylan RenneyGang Gang Dance performed at Bumbershoot on Saturday, September 5.Who: Gang Gang DanceWhen: 7 p.m., SaturdayWhere: Exhibition HallLiz Bougatsos is one of the most beguiling performers I’ve ever encountered, and while she’s a beautiful girl wearing a doctored, oversized shirt with the collar cut off and most of one bra strap hanging out, that’s not why she’s so fascinating to watch. It’s because Bougatsos is one of those rare individuals who throws every single ounce of her body into the music — not the performance. Her undulations are completely and totally in sync with the rhythm, whether she’s slinging drumsticks or flicking hair out of her eyes. By the time the show ended, she had raccoon eyes from her make-up running and her hair was so wet with sweat she might as well have just gotten out of the pool. But Gang Gang Dance’s music is just as captivating as she is — a percussive synth assault overlaid with Bougatsos’ voice, which sort of resembles Kate Bush’s when she sings in a high register. It was unfortunate that more people in the crowd weren’t dancing, but she and the music were both so hypnotic that I can’t fault anyone for stopping to really watch and pay attention instead of trying to clumsily emulate Bougatsos’ superior dance moves.