A test mule for one of the greatest supercars of this century is up for grabs and could fetch more than $1 million.

The 2012 Ferrari LaFerrari Prototype is every bit a working prototype, with extraneous testing panels included in the sale and a taped-on note on the steering wheel advising drivers to be careful because the car has not been tuned to go full-throttle. The prototype is a "first-phase test mule," according to RM Sotheby's listing, and the buyer will be getting a semi-formed LaFerrari and a part of automotive history, as the LaFerrari has only grown in esteem since its debut in 2013.

The prototype, even today, is not street legal or even fit to be used on most tracks, because it was never homologated and therefore lacks a lot of safety components. It is drivable, however, and the listing says that it will be serviced before delivery to the winning bidder, "to ensure the car is in running and driving order."

The test mule is powered by a V-12 engine, likely making around 700 horsepower. It's based on the aluminum chassis of the Ferrari 458 -- and not the carbon monocoque that the LaFerrari would eventually be built on -- and was mainly used for testing brakes, according to RM Sotheby's.

It was also the first LaFerrari test mule, called the "M6" internally, and built in early 2012. For over a year, it was then used and abused for testing, much of it on Ferrari's Fiorano track. More than the brakes, the LaFerrari prototype, "used for development of the suspension, brakes, steering, and tires for the LaFerrari as well as being the LaFerrari prototype first fitted with the LaFerrari-specific Electronic Stability Program (ESP) system," according to RM Sotheby's.

The prototype comes with a so-called "Yellow Binder," which details all the things Ferrari did with it, and which was sold alongside the car in 2016 when Ferrari was selling some of its LaFerrari prototypes. This one will mainly be of interest to serious Ferrari collectors who already have one or several Ferrari supercars in their collection, probably a LaFerrari too. They can say this prototype was one of the greatest supercars ever made before the LaFerrari was.

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