What is gnome kmogski in left for dead 2

gnome chopiliski or i cant spell its name its a gnome you try to win in the left for dead 2 dark carnival part 2 you can use it to wack zombies and if you last 5 levels until you survive and beat the concert with gnome chopoliki you get an acheivement it will be hard make sure you take your time and try to find gnome chopoliski