Some of the very first vehicles were pulled by animals, but having horses and mules pull us around went out when motorized vehicles came in. Today, with oil reserves dwindling and environmental concerns looming, more and more of us are looking back toward animal-powered conveyances to get us around. The Naturmobil is a controversial horse-powered contraption that puts a bizarre new spin on the horse-drawn carriage.

The basic idea of the Naturmobil takes the horse-drawn carriage and turns it inside out: instead of walking in front of the vehicle and pulling it, the horse is inside, walking on a treadmill. The horse’s movement moves the vehicle forward and charges its batteries for when the horse needs a break.

The Naturmobil’s inventor says that it is the ultimate nature-friendly vehicle. While putting a horse inside a glass container and making it walk on a treadmill may not seem great for the horse, the inventor also insists that the invention is entirely safe for the animal. It’s kept out of the elements, doesn’t have to pull the heavy cart, and can take a rest when it’s tired of walking.

The unconventional vehicle’s top speed is around 50 MPH, though it’s designed to roll along at about 12 MPH. It’s meant only for use on paved roads and only has room for the driver, one passenger and the horse. This crazy car may not ever take the place of conventional cars – or even normal horse-drawn vehicles – but it could be useful in convincing more people to look for alternative sources of eco-friendly transportation.