The thing is simple enough: a receptacle attached to a long rod with some tape to make for a universal (any-direction) joint, and four thin cables or rods attached at the corners of said receptacle attached at the end to a cross, which allows the user to manipulate the receptacle similarly to the way a puppeteer controls a marionette.
It's a simple device that can be built for the purpose of trapping any animal small enough on any sufficiently even surface.
The issue of the actual obtaining of the trapped animal was never entirely resolved. What we ended up doing was sliding a plastic sheet between the receptacle and the wall, like the way one traps big scary spiders. Improvements are welcomed: the blueprint has been released under the GNU FDLv1.3 license and if you have an idea, you can download and adapt the vector graphics file linked below, or email me and I can update the design, with credit to the inventor, if desired.