Just a mole trap. I think that's what they are called. Kind of expensive, especially when it traps a mole and the coyotes come in and haul the trap away, never to be seen again. He (friend) has lost several mole traps that way. As far as it's functionality, basically, you dig on or near a mole hill till you find the mole's tunnel and place the trap in the tunnel you think the mole might be in. It crawls into it thinking it's the tunnel, and when it's roughly half way, it hits a large lever that triggers a spring loaded latch release and a steel wire clamps around it's body crushing him like a python. Works very well.
OH I don't know giant moles might make a good alternative food source, probably just need extra Red eyed hog seasoning