I love Daleks and Cybermen because they're illogically terrifying: The clumsier the tech, the scarier they get. Nemo Gould's found-material sculptures unlock the same secret brain code, being cartoony and scary at the same time.
Check out the videos—they're practically immobile, but remain menacing.
If you want to build a Mantis of your own (like you ever could!), you can read how Nemo did it on Instructables. [Nemomatic via BoingBoing]