As "The Voice" contestants battle their way through the playoffs, the usual round of exciting big name pop stars are coming by. Last night's show featured Sia performing "Elastic Heart" on the show. The singer, per her usual style, appeared in a big blonde wig (and a big floppy hat), with the bangs totally obscuring her face. Not in attendance, sadly, was her pint-size dancing alter ego, Maddie Ziegler, but it was a school night, after all. Also not there was Shia LaBeouf, who appeared in the video for "Elastic Heart" alongside Ziegler. Maybe it was a school night for him as well?

Watch the whole performance below. How do you think this latest crop of "Voice" contestants is shaping up? Can they learn a few things from Sia about holding a crowd's attention without needing any stage pyrotechnics?