The Mooning Santa is an animated Christmas Decoration made in 2004-2006. It features Santa Claus standing on a tan base. When push button or motion activated, Santa says "Since you've been extra good this year, Santa's got an extra special surprise for you." Then, Santa turns and drops his pants as he says "Merry Christmas" and laughs hysterically.
There is also a plush one that says different phrases, a version with the one phrases' design, but with the plush's phases, and a plush one with the phrases and sings shake your groove thing
Mooning Santa in the box
15905 Gemmy Mooning Santa
Mooning Santa in action