in 1987 Predator movie, what is the gun type used by the alien creature on his shoulder?
Does it shoot bullets like a normal gun or is it a Plasma Gun?
It is a Plasma caster which is fired from the shoulder of the Yautja and it fires a plasma pulse, not bullets.
The plasma caster is a shoulder-mounted energy weapon. A triangular laser rangefinder is used to assist aiming the shot. The laser sight can be part of the Predator's helmet, although some casters have their own laser sights without need of a helmet. In both set-ups the plasma caster moves with the Predator's field of vision. It fires a bright blue or gold plasma pulse in a straight line. The pulse can be controlled to fire with more powerful charges ranging from minor stunning/wounding blasts or powerful enough to sunder the atmospheric plating of interstellar aircraft. The plasma caster and respective tracking servos are some of the most vulnerable articles of equipment carried by the Predator, being easily damaged. The plasma caster can also be used as a hand held weapon.