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.