I once read that small hand tools mutate into coat hangers... which, of course, explains why small tools constantly disappear (sometimes as quickly as "where the heck is that screwdriver? I remember just putting it down on that air filter box"). And, further explains why coat hangers seem to multiply in the hall closet without explanation.
Personally, I believe that there are gremlins that live under the hood of most cars. Their most clever trick is to suddenly release an extraordinarily tight bolt just as your pressure on the wrench is beyond the point of any possible restraint, and your knuckles are less than an inch from a hard object. These gremlins live on small hand tools... especially 10 mm deep sockets.