I swear this is true, just happened a few months ago. I was sitting out in my truck in the parking lot eating lunch around 1 am. Out of the corner of my eye I spotted some kind of creature walking along the highway service road alongside our building. Not uncommon to see coyotes, raccoons, cats, or other critters since we were near a big wooded area.

But this thing was 2-3 feet tall walking upright. Well not really walking, so much as sort of levitating along slowly. It was pretty dark out, but I could just faintly see this thing making its way on down the road. Really kind of freaking me out because I wasn't quite sure what I was seeing. Fumbled my camera out but couldn't get a good picture of it since my flash was useless. Pulled out my pocket flashlight but still couldn't quite make out what it was. Seriously, my heart was racing because I was certain this was a legit cryptozooilogical encounter!

Then I had the bright idea (heh) to turn on my headlights since I was sitting in my truck facing this thing. Lit it up and had a brief moment of confusion followed by relief it wasn't Chupacabra followed by laughter.

Turns out it was one these floaty Chucky Cheese helium balloons with arms and legs that hovered slightly along the. Darn thing had somehow lost its head, but must've gotten loose from some kid at the Chucky Cheese about a half mile down the road. I just giggled as I watched it hover on along the way into the darkness of night.

My background is rather convoluted, I am British. I studied Medieval history to A-level, trained as a locksmith ( the last year it was legal to practice non-destructive entry (lockpicking). Moved to Munich as an historical beer tour guide and Second World War guide both there and Dachau. Went to Uni to study "History and philosophy of Science with Russian History and Literature". First and only year this course was available, one of two who took it and both of us withdrew early in second year. It was impossible to complete, more contact hours than any other course and was running all over campus! Went on to train under my uncles as a structural carpenter. I am now 33 and still an avid amateur historian and general f*****t.
The following is a non-cited but pretty d**n accurate spiel...
The use of booby traps is far more common than you would think. There are examples that extend back over five thousand years. The most common is the use of water diversion. Dating back to the babylonians and Hittites, there are examples of cantilevered stone walkways that open outlets that would flood a chamber when depressed/triggered. They have been negated though due to rivers naturally being diverted due to erosion etc. Drop falls were pretty prevalent, but again, the sheer passage of time have gunked up the mechanisms or the pits have been filled by the slow ingress of sand/soil.
There are examples of large stones designed to fall on invaders, but much akin to wall bows (where bolts fire from wall apertures) the potential energy storers (whether a crossbow like strap of tendon or suchlike) the passage of time has denatured them past use.
It is my, admittedly meagre, understanding that the most advanced of these traps were developed in South America and Egypt (including sand traps(nasty, they use weight displacement to allow sand to flood in (f**k drowning in sand).