The Before Christmas is the eighth couch gag of Season 25.
The Simpsons run in the living room and stand in front of the couch with Santa's Little Helper, and the frame turns into a Victorian painting of the Simpsons (with Santa's Little Helper as Rudolph). The words, "'Twas the Couch Gag Before Christmas", appear above the family.
This is a Christmas couch gag, and the third episode that the couch gag continues into the TV. It's also the first time since "Lisa The Drama Queen" where the screen cuts to black. In this couch gag, the Simpsons do not sit in the couch.