Michelin designed the PLR (Poids Lourd Rapide, or fast semi truck) in 1972 as a way to test out truck tires at high speeds without the risks of using actual trucks; if a tire blows they don't have to worry about losing control of their vehicle.
This borrows heavily from Citroen's parts bin - it was easy for them to access it since at the time Michelin owned Citroen. The ten wheels and hubs come from an HY (aka Tube) van and most will recognize the DS parts in use throughout it all.
Michelin's engineers fitted two Chevrolet 350 engines in the back. One drives the car, the other drives a mid-mounted truck wheel (see below) that is fitted with a test tire. The rear six wheels power the car while the front four steer it.
Nicknamed "milles-pates", or centipede, it supposedly has a top speed of 180km/h not bad for a vehicle that weighs about ten metric tons.
Note: I did not take any of the above photos and do not take credit for them.