I’m glad that humans are much larger than beetles.
This is a stag beetle, a proud member of the beetle family with the big (and usually very intricate) jaws.
This is how I found it… living with a new-in-box oil filter, in the basement. I took it outside to snap pictures.
It stood up and tried to make itself look as menacing as possible. Those jaws look like they mean business.
For size reference, here it is with the peel-off part of a milk jug. Either it was weak from living in the basement (I mean come on, what could it possibly eat on the inside of an oil filter box? Certainly not the filter), or those jaws aren’t as menacing as they look; it bit the plastic in about as much time as it takes you to gulp nervously.
At several points, it stood on its hind legs almost vertically, seemingly to either scare me off or engage me in some sort of biting match. I turned it loose in the yard.