The Pikamobile is a themed Volkswagen Beetle vehicle that is made to resemble Pikachu. Many of them existed in the United States to help promote the Pokémon franchise.
History with the Macy's Parade
One of the cars was first seen in the 2001 Macy's Thanksgiving Day Parade as a companion to the newly-introduced Pikachu balloon and appeared before the balloon. From 2002-2004, as well as 2006, the car appeared after the balloon.
The Pikamobile was supposed to appear in the 2005 Parade. However, this never happened, leaving the Pikachu balloon travel the route alone.