Crocs and built almost entirely from foam. In fact, 90 percent of the Spira's makeup is foam, which doesn't exactly give us loads of confidence about its ability to withstand major (or minor, really) impacts on the American freeway. At any rate, this 302 pound automobile -- which can hit a top speed of 70mph via a 100cc engine -- is expected to make a literal splash in the Progressive Automotive X Prize, though we kind of doubt you'll ever see this thing mass produced in its existing form. Have a look at a pretty ridiculous video just past the break to see what kind of fun we're all missing out on.
[Via Wired, thanks Eric]