Abstract: A novelty device attaches to the exterior of a motor vehicle, with an upwardly extending arm producing a passive lateral oscillation due to vehicle motion to simulate a wagging animal tail. The device includes a base plate which attaches to the vehicle between a license plate mounting area and the license plate, with a bracket extending outwardly from the plane of the plate. A laterally flexible arm is attached to the distal end of the bracket. A fabric or plastic sleeve resembling an animal tail may be installed over the arm, so the covered arm resembles the tail of a team mascot animal or the like. The flexibility of the arm may be adjusted or varied by providing a series of bends at the base of the arm or elsewhere along the arm, and/or providing a bobweight at the distal end of the arm or elsewhere along the arm.