Typical for the time before Christmas is the Krampus. It is a dressed person with a scraggy costume, a scary mask and noisy bells around the hips. Originally the Krampus is the companion of St. Nicholas who arrives on the 6th of December to award nice children.
As processions with the Krampus are becoming more and more popular they already start a few days earlier. But if you see a person dressed up as Krampus after the 6th of December its probably a Percht follower. They look very much alike but the Percht followers usually arrive on December 6th, December 22nd and January 6th to cast out winter.