You walk through a sort of pre-show, where you find out you will be witnessing a demonstration of a new teleportation device. You see a brief demonstration in the pre-show, using animatronics. This demonstration goes wrong, with the cute, furry alien subject getting fried. But the host blows it off.
Then you go into a big room with rows of seats encircling a teleportation chamber in the middle of the room. I believe you have an over the shoulder restraint on. Somehow, instead of a friendly scientist being teleported to the room, a vicious alien is teleported. The lights go out, and you hear a lot of screaming. There's little air vents and speakers on the back of your seat to make you think the alien is right behind you sometimes.
The alien also slashes somebody, which of course you cannot see because its dark, but water is squirted on you to make you think its blood.
Eventually, they get rid of the alien, and you leave.
How this will affect you all depends on how "into" the experience you get. Some find it simply terrifying, while others think its just a bunch of hokey air blasts and water effects.