Anyone who's played Mario Kart knows the terror of seeing these shells bearing down in their rear-view (not the blue! Anything but that!). Now these leader-seeking missiles are coming to the real world in the form of adorable R/C racers.
As his homage to the Mario Brothers universe, Skimbal, designer of the super-popular Gothic Cathedral Play Set, has released everything you need to print and build these racers—from the STL schematics, complete list of materials, and assembly instructions—for free, at Thingverse. You just need to provide your own 3D printer.