In Norway, families hide their brooms on Christmas Eve to prevent what from stealing them?

Witches and spirits

In "Big Hero 6", what's Hiro's brother's name? Who sang the viral 2012 K-Pop hit "Gangnam Style"? Which singer released the hit "Watermelon Sugar"? Which South American nation has a city named Guayaquil? What is a solid shape with twenty triangular faces called?