Looks like an oversized mouse-trap to me. The mouse version breaks their back and they die almost instantly.
My concern with the above is that it might injure an inquisitive cat or dog. Two of our family cats each had one of their back legs smashed by some kind of animal trap when I was young. They managed to drag themselves home (which was rather traumatic to my five-year-old sister, as one of the cats was hers). One of them had to be put down; thankfully, my sister's cat survived but lost the leg.
