A thing posing as a dog is shot at but is not hit; later, a dog is eaten by the thing while several others escape. The Thing's body, half-transformed into a dog, is shown multiple times.
Fire is one of the primary weapons used. A flamethrower is used defensively; the Thing while posing as a man is burned alive; torched bodies are shown after the fact.
Yes, there's a scene where all of them draw blood by cutting their thumb/hand with a scalpel. There's also use of a scalpel for a dissection earlier on.