[Pi Is Exactly 3]

I think the thing on his shoulder is like a cannon of some sort, but I believe the Predator had the ability to see in infrared which (when shown in the movies) looked like things were different colors much like our camera sees. Arnold had to cover himself in mud to eliminate the Predator's ability to see him because he looked like an orange blob to the Predator.


It's been a while since I've seen the movies, so its just a guess.