I like Peter's answer! LOL A friend of mine got so upset with his unwelcome guest that he built a contraption that he calls "GROVER" (I thought it was an acronym, but it's apparently named after the guy who told him how to build it!)

Imagine a slab of concrete about a foot square, with a jerry-rigged mousetrap in the center. When the dirt around the trigger is aggitated, the trap shuts onto a compartment with a shotgun shell in in. Kablooey. If the shell doesn't get them, then the blastwave does (that concrete ain't going anywhere).

He has no plans on patenting the schematics, so anybody that wants a GROVER....