MacReady (Kurt Russell) or Childs (Keith David) is still infected with a body-snatching alien. One of the most popular and long-standing theories about the end of “The Thing” is courtesy of Dean Cundey, the film's cinematographer.
As The Thing follows MacReady's perspective, it's not likely that he was secretly assimilated. Of the two, Childs is far more likely to have been infected, but the nature of the Thing makes it impossible for either man to trust the other. However, the most likely eventuality is that neither man is infected.
The eye light theory states that humans were marked with a light in their eyes by the film's director of photography, Dean Cundey. At the end of the film, Childs does not have the eye light, and MacReady does.
The movie's ending is famously ambiguous, with Kurt Russell's MacReady and Keith David's Childs the only two men left alive. It's left up to viewers to decide whether the alien lives on in one of them.
Russell stars in the film as MacReady, one member of a doomed Antarctic research team, who faces off against a shape-shifting alien being. The final scene of the movie famously sees MacReady and Keith David's Childs as the only survivors, though it's not revealed which one is actually the alien.
Cundey suggested that throughout the film a specific light gleam can be seen in the eyes of whichever body is currently inhabiting the alien. A light gleam can be seen in Childs' eyes in the final scene, which would mean he's infected with the Thing under Cundey's theory.
After some destruction, both Gary and Nauls are killed by The Thing, but MacReady seemingly manages to take out the threat with a series of massive explosions. After finding any kind of cover from the explosions and cold, MacReady finds himself toe-to-toe with Childs, who'd gone missing a bit earlier.
MacReady returns in the 2002 video game sequel to The Thing to assist the U.S. Rescue Team investigating Outpost 31 in destroying The Thing. MacReady's survival is never explained, though the game is set 3 months after the events at Outpost 31.
What happened to the girl at the end of The Thing?
In addition, the film's writer, Eric Heisserer, revealed in an interview with the website Bloody Disgusting that in the script he wrote, Kate did not survive.
You've read the other theories, now bask in truth: MacReady is infected and has been throughout the film. Carpenter wants you to assume Childs has been infected while off-camera during the climactic finale, hence MacReady's questioning as they sit amongst the warm flames that engulf what's left of their outpost.
So they set explosives to destroy the station, but the Blair-Thing kills Garry, and Nauls disappears. Blair-Thing transforms into an enormous creature and breaks the detonator, but MacReady triggers the explosives with a stick of dynamite, destroying the station and the monster.
As predicted, the vast majority of the prequel's characters are dead by the time credits roll, though Winstead's Kate has managed to (at least temporarily) stop the monster from escaping Antarctica in its spaceship. The Thing 2011 ends on an ambiguous note for Kate, though the original script made his fate very clear.
While there are convincing arguments that Palmer was the original, most fans subscribe to the idea that Norris was the first to die. His character is one of the least seen in the movie but is conveniently one of the first to appear every time some major event happens.
The most common read on the ending of "The Thing" is that Childs is most likely a Thing, and there is some logic to that line of thinking. Childs disappears for the entirety of the finale until the very end when he comes back with a pretty bogus excuse of why he was gone.
MacReady, Garry, and Nauls agree that the Thing cannot be allowed to escape and set explosives to destroy the station, but the Blair-Thing kills Garry, and Nauls disappears.
There are existing stills of an alternate death for Fuchs. Like in the film, exactly what happened would be ambiguous and open to interpretation, but rather than finding his corpse being found burned in the snow, he would have been found in a greenhouse impaled by a shovel. The scene has never been released.
MacReady was a level-headed leader who kept everyone in check, hence why he is one of the best characters in The Thing. So the Thing was smart to frame him as an imposter, leading to disarray in the crew.
For example, in the blood test scene, the Palmer-Thing is tied up arm-to-arm alongside Garry. Yet the blood test proves Garry is still human and he is later assimilated for his troubles. Instead it's far more plausible that Norris was the one first assimilated during the dog encounter.
One possibility as to how this came about was when two dogs escaped the kennel once Clark opened the gate. It is likely they would have been infected once the Thing had emerged.
MacReady then hands Childs the bottle of whiskey. He drinks from it and MacReady smiles to himself. Now the popular theory is that Macready had filled the bottle with gasoline. As Childs drinks from it and there is no reaction this is why the pilot is smiling.
The most terrifying aspect of the iconic horror creature The Thing is that nobody knows what it looks like or has seen its true form. The extraterrestrial's entire existence is based on assimilating and replicating the appearance of other organisms, so it's difficult to determine exactly what its original form is.
As in the final version of the film, Kate was the central protagonist and a palaeontologist, as well as Thule Station's last survivor (not counting Lars and Matias), killing Carter after discovering he'd been assimilated. that Kate does not survive in the script he wrote.
