Continuity mistake: When they are all outside and MacReady has separated the three most likely suspects and orders that they be tied down and tested, he comments at that time that they are to be hit by a storm in six hours. Cut to the scene where Mac is dictating into his recorder and he comments that the storm has been hitting them hard for 48 hours. However it is the same night and at best, maybe only an hour has passed.
Continuity mistake: When Mac is locked out of the complex by the rest of the team, who think he may be a 'Thing', Childs uses an axe to try and chop open one of the doors, leaving a HUGE hole in the middle of it. Later Childs returns to that same door and the hole is significantly smaller and at a completely different location on the door.
Continuity mistake: When the crew is outside and they're going to lock Blair in the tool shed, you can see someone nailing wood across the window on the front of the shed. The pieces of wood are horizontal. In the next shot (inside the shed), if you look at the window in the background, the strips of wood are vertical. When Mac goes back outside, the wood is horizontal again.
Continuity mistake: Each man only dribbles a few drops of blood into the petri dishes as their blood samples. But when the test is administered, there is a lot more blood in each dish, enough to cover the entire bottom.
Continuity mistake: When the Doc and Kurt Russel enter the burnt Norweigan building the door closes itself behind the Doc. It closes and opens several times over the course of the scene.
Continuity mistake: When the dog, aka the The Thing, is led into the dog pen for the first time we see the floor is covered in a thick layer of straw for the dogs to sleep on. This is seen every time except when Childs uses the flame thrower. We get a wide shot of the pen as it's lit up in flame and the floor is now completely bare of any straw. There are also none of the recently deceased dogs that were lining the floor, being converted into Things. (00:31:05)
Continuity mistake: Just a couple of minutes into the movie, Gary shoots dead the crazed Norwegian and the camera returns to MacReady. Now watch closely: When he gets up to help injured Bennings, he and his Jim Beam bottle are covered up to the hilt with loads of snow. But on the next shot, a split second later, his clothes are miraculously clean and the whiskey bottle as dry as you can possibly get it. (00:09:00)
Continuity mistake: When Doc is trying to revive Norris and his arms fall into Norris' chest, he is wearing long sleeves down to the wrist. In the closeup of Doc's arms being ripped off, the sleeves are pushed up to the elbows and the forearms are bare. (01:15:15)
Continuity mistake: When the stray dog is placed in the cage with the other dogs and starts to mutate into The Thing, one of the other dogs start biting a hole in the fence. We get a clear view of the hole in one close-up, and in the next shot as The Thing sprays liquid on the dog, and the hole in the fence is much bigger. (00:27:45)
Continuity mistake: When the three men are shown finding the UFO from the front, their hoods are down. In the next scene, from behind, their hoods are over their heads.
Continuity mistake: When Kurt Russell first looks at the chess game, amount of ice in his glass changes between shots.
Continuity mistake: When the thing is on the lab table, and the severed head starts walking away, Mack torches it with a flamethrower. At one angle, you can clearly see that fire is not coming out of the hose. It is just a fire going off in the doorway. (01:17:20)
Continuity mistake: When the remaining men find Macready holding a flare to a bundle of sticks of dynamite, the sticks go from being loosely and haphazardly bundled together to tightly tied together and then back again in a matter of seconds. (01:12:45)
Continuity mistake: When Palmer, as the thing, picks up Windows by the head his wardrobe is different as soon as he picks him up. The sleeveless motorcycle jacket he is wearing is missing and he is just wearing the green short sleeve shirt and the white sweatshirt. Then in the next shot he has the sleeveless jacket on again. (01:23:40)
Continuity mistake: When Kurt Russsell first goes to the crazy guys' shack, he puts a bottle down with the label facing forward. When he leaves it is facing the other way.
Continuity mistake: After the Norwegians exit the helicopter, one of them goes to throw a grenade but accidentally lets go of it, and it explodes. In the shot where the man takes cover during the explosion, the fire clears out and there is soot around the helicopter on the snow, about six feet. A couple of shots later, as the Norwegian stands up, the amount of soot around on the snow has notably increased. (00:08:20)
Continuity mistake: When the helicopter is circling the research station, the co-pilot picks up a hand grenade to throw on the ground. He picks up the grenade on the bottom row in the middle column. There is no grenade in the middle column from the second row of grenades and no grenade in the left hand column of the top row of grenades. Around 45 seconds later, in the shot after the dog leaps onto one of the researchers, the exact same shot of the man taking the grenade out of the box has been repeated a second time. He takes out the exact same grenade from the exact same row. (00:07:15 - 00:08:05)
Continuity mistake: MacReady and Doc return to the research station from the abandoned shack in the helicopter. The scene then cuts to the dog watching the two exit the helicopter in the window. In the shot where the helicopter is visible in the window, the dog is looking out of the window from the right hand side. In the next shot, it is suddenly looking out of the left hand side. This mistake has nothing to do with the angle of the camera. (00:22:35)
Continuity mistake: After MacReady and Doc have discovered the spacecraft, the scene cuts to a wide angle of them approaching one of the researchers looking into a dug up hole. Just as the wide shot ends, MacReady and Doc are standing right next to the man. The shot then cuts to a closer angle of the three and MacReady and Doc are now several feet away from him. (00:39:50)
Continuity mistake: After the scene where the Norwegian helicopter chasing the dog through the snow ends, the scene cuts to the research station. The first shot from the research station shows a sign: UNITED STATES NATIONAL SCIENCE INSTITUTE STATION 4. This close-up shows scratching and rotting all over. A few minutes later, as the helicopter arrives at the station, the scratching and rotting over the "4" is no longer there. (00:04:30 - 00:06:15)
Answer: At the end, the large creature presented itself as an amalgam of beings it had absorbed-part Blair, part dog, and various other beings with tentacles, insect-like legs, and a worm-like body. I don't believe that we really ever see what its true form is, if it has one.
Erik M.