The Cloud B4 carrier (also known as Whitley-Thing) is a massive Thing Beast created from Colonel Whitley through the use of the experimental Cloud virus. It served as the final boss of the game.
It appears as a towering monstrosity. From the middle and lower part it had several tentacles. From the top it had multiple arachnid-like legs and a fanged, gap-like mouth at the center. The only remaining part of Whitley was his head.
Shortly after Whitley's brief encounter with Blake, he began to feel the side effect of the Cloud virus he injected earlier and mutated into a massive creature, luckily for Blake a helicopter pilot (who is later revealed to be R.J. MacReady) assisted Blake in confronting the creature. Blake uses the helicopter's mounted machine gun and used the nearby fuel drums to his advantage. The creature was finally destroyed, Blake escapes the Antarctic via helicopter.
The first main targets are the four fuel drums which are near the bottom of the boss, it may seem a little hard to hit at first because the chopper is moving a lot. But as soon as you get all four of them the gun will turn upwards towards the upper torso of Whitley Thing. Here you will see that a long tentacle comes out of his body in a certain position and then it goes back in. That is its weak spot, keep on hitting him there and soon you should finished the Thing.
- Given that the Thing can't generate mass from nothing and needs to assimilate biological material to take larger forms, it's strange how Whitley gave rise to this form without assimilating other life forms, unless he assimilated something.