R. J. MacReady, played by Kurt Russell, is a fictional character and protagonist in the 1982 film The Thing.
MacReady is one of several Americans stationed at U.S. Outpost 31, an Antarctic research station. He is initially seen playing a computer version of chess. After he loses, he pours his whiskey into the computer, destroying it.
Moments later a sled dog approaches the facility. It's being chased by a Norwegian helicopter where a passenger is taking repeated shots at it, trying to kill it. The helicopter lands and is inadvertently blown up from an errant grenade. They take the dog in and it reveals itself to be an alien creature and assimilates the other dogs in the kennel. Childs is forced to incinerate the dogs but not before the alien creature disappears into the ceiling.
MacReady and Dr. Copper fly to the Norwegian camp where they find it in shambles with everyone is dead inside. They find records of a discovery of an alien spaceship and a creature they found encased in ice. Back at the American outpost, Blair autopsies what's left of the assimilated dog and discovers that what they're dealing with is a creature that can take on the form of the person or thing it replaces.
One by one the outpost members are assimilated and trust wears thin. By the end, everyone is dead except for MacReady and Childs. the two of them sit by the burning remains of the outpost drinking whiskey as they slowly freeze to death, neither knowing if they other has been assimilated or not.