I first saw this over on BoingBoing, where it was mentioned (jokingly?) as a good punishment for rowdy toddlers.
Not so sure about that one, but as soon as I saw this, I immediately thought:
“The rabbits. I should get one of these to keep the $*^!$*!*ing rabbits out of the garden.”
Pretty pricey at $649, but we lost about half that much these past few years in girdled trees… so really, how much is sweet revenge worth?