The Slides show a humanoid about 3 feet long, somewhat elongated head with a large cranium and a small, underdeveloped mandible, with a face that was relatively human-looking. The nose short, but within the range of "normal" human proportions. The eyes were round--maybe slightly almond shaped--but also well within the range of "normal" human proportions. They were not at all "insectoid" looking. The ears also located about where they would be on a normal human head--about half way from the chin to the crown of the head. The mouth had thin lips (human-like--finer and flatter). The mouth is open and no teeth are visible The skin as being chestnut brown. The skin of the humanoid is smooth and appears to have shrunk taut against the bones (ribs, legs, arms, cranium). Whether this is due to natural effects of death (saponification, dessication, etc.) or is the result of some post-mortem treatment (embalming, freezing, etc.) is not clear. The head appears to have been severed from the top of the spinal column and then replaced, lying at an unnatural angle relative to the torso.
RR
As mentioned by Starman, these beings certainly don't seem to be invincible. I mentioned earlier that if they are biological beings,which would seem to be the case, they probably can have an "off" day, same as us. Maybe they get tired, get hayfever...get "dear John" postcards from the missus.
KR jokingly mentioned above that "someone might have pressed the wrong button". That's not an outlandish theory to me. In one of the books in my vast collection...about 20 paperbacks :-( ... I remember reading an interesting point being made by the author (was it you Kevin?...might be Tim Good) that in some reported cases, the ufo's act like they are being piloted by juvenile delinquents secretly taking daddys car out for a drive. In the JAL case mentioned by Larry above, this UFO the size of two Nimitz class carriers was practically showing off!
Some reports suggest that UFO's could be accused of playing "chicken" with our pilots. Playfully buzzing them.
It's quite feasible to me that some,off colour, or cocky alien pilot could have made a "pigs ear" of it.