Recapturing the hotly contested Guinness World Record for lowest street legal car from friend of the Jalop, Andy Saunders, the Flatmobile is just 19" tall. Based on a Hillman Imp, it uses that car's rear-mounted 875cc engine for propulsion, supplementing that with a jet engine made from an old turbocharger. Pictures below the jump.

Perry Watkins, of Aylesbury, England says he was inspired to build the car one day when he was out and about, suddenly thinking, "it'd be smart to have something that looks like the Batmobile, but call it the Flatmobile." Since his next thought was, "hold on, let's put a jet engine in it," he sounds like our kind of guy. Perry describes the Flatmobile driving experience as, "horrible," but it is road legal.
[The Flatmobile]

Thanks to Gilles and Beercheck for the tip.