Crab and crayfish, two cute crustaceans, as cool compliant contraptions!

These small (and somewhat educational) toys print as one piece without support. 

Stick your finger through the hole to hold them and pinch your fingers to pinch whoever stands in your path. 

Features a guide rod that also stops the mechanism from opening too much. 

I printed them in PLA with a .5 line width. Infill doesn't matter much, 5% should be enough. Be sure to have enough tolerance so the guide rod doesn't fuse to the channel.

Pause and switch filament just before the eyes to make them a different color, or color them in the slicer if you have a multicolor printer.