TRAP! by idea_beans is one of my favorite prints on Thingiverse. I love all things mechanical and this one is so well done. It prints great, goes together with just a bit of fitting, and works and looks awesome.
The only problem (as others have pointed out) is that one of the jaws didn't lay flat when set. While this didn't affect the overall performance of the trap it just didn't look right so I came up with a simple fix. I couldn't edit the STL so I had to remake the jaws completely from scratch so they are a bit different from the original but the main difference is I put a simple notch and hook on the ends so the right jaw locks open off of the left jaw keeping it flat when set.