A Giant Spider and Small Knife
A 100% 3D printed knife seems unlikely to be successful (at least in plastic) but it actually works. Of course, not as well as a metal knife but for specific applications a plastic blade can get the job done. Plus the design is cool and novel. I am using it for cutting packing tape on packages that arrive and it works really well. Check it out.
My latest version of the giant spider is a redo from last year with a revamped body, snap together latches for assembly and improved click joints. The spider is very large and fully articulated so you can pose them however you want for maximum fright on halloween night.