The Grandfather Moose Clock is a clock in The Addams Family Mansion.
It is made from Pierre's stuffed hind quarters. The tail switches on the half hour and goes all the way around on the hour. It is mounted on a Living Room wall directly across from Pierre so that he can see himself as the world sees him.
Though he appears in many episodes as mere decoration, he is given more screen time in The Addams Family original series episodes: