Fan Casting The thing

In remote Antarctica, a group of American scientists is disturbed at their base when, from a helicopter, someone shoots a camp dog. As they rescue the shot dog, the animal starts attacking the scientists and the other dogs, and soon they discover that the animal can take the form of its victims. This means that team members can be killed and the copy takes their place. With that, a pilot and a medic need to capture the beast before it's too late.