Harry's Dog Van is a van formerly owned by Harry Dunne who used all of his life savings to turn it into a dog van in Dumb and Dumber. He stated that the alarm alone cost him $200. After Harry and Lloyd got stranded in Nebraska and had no money and gas to get to Aspen, Colorado, Lloyd sold the van for a minibike so they will be able to have a ride to Colorado.
They manage to reacquire the van in the TV Series, with it also being named Otto, though this was in no way related to the original storyline.
The van also makes a cameo appearance in Dumb and Dumber To when Harry and Lloyd come across it on their way to El Paso, Texas. The both of them try to see if it still works after 20 years, but sadly it brakes down and falls apart, so they instead use a stolen Zamboni ice resurfacer which becomes their new vehicle to get back home to Providence, Rhode Island on the way back.