Babymetal - Summer Sonic 2017 Highlights: Highlights from Babymetal's second day performance at Summer Sonic 2017, October 18, 2017. Babymetal's set worked as serious stadium-filling fare. Opening with a slideshow of its history at Summer Sonic including a 2012 performance in the food court that showed just how far this Japanese phenomenon has come. Nonstop energy with the trio dancing and commanding the audience to lose it while their backing band shredded away.