This Christmas Vacation t-shirt shows Clark W. Griswold peeking into his Christmas tree. The shirt reads Squirrel! In Christmas Vacation, the Griswold's family Christmas tree was scorched by Uncle Lewis's stogey. Clark Griswold decided to cut down a new tree from his yard. The only problem with the new tree was that it housed a squirrel. When the family heard a funny squeaky sound, Clark peeked in the tree, and squirrel jumped out at him.