The more monstrous transformations of the thing look horrifying even in well-lit, motionless, on-the-set photos while surrounded by a film crew. That's the result of fantastic creature design. "The Thing" would have been effective whether done in CG or not, but I have to agree that acting out appropriate fear must have been a little bit easier for the cast of "The Thing" thanks to the monster being so vividly realized on the set.