Disney Imagineers worked with filmmaker George Lucas to develop this scary, darkly humorous alien experience. Guests are introduced to X-S Tech, a company located on a faraway planet that is pitching its interplanetary teleportation device to earthlings. A sales robot gives a demonstration using an appealing little alien named Skippy. Unfortunately, the device has not yet been perfected and Skippy appears charred and disoriented after his short teleportation.

Next, guests enter a circular demonstration chamber where they are harnessed into their seats around a large tubular teleportation device. The beam once again malfunctions and a huge and frightening alien materializes. Furious to find himself captured, the alien smashes the glass tube and escapes into the chamber. Suddenly there is a power outage and the audience is plunged into total darkness. Everyone is certain the alien is about to attack them. The seats vibrate with the creature’s footsteps, his breathing and heartbeats are clearly audible. Even his warm moist breath is felt. If not yet convinced of imminent bodily harm, water sprinklers and air blasters mounted in the row in front were used to simulate either the dripping of the creature's drool or blood from an attacked worker in the scaffolding above the theater.

Soft textile tubes attached to the seats had air blown through them, causing them to slap against the back of the head of each guest. This was the most direct physical effect, used in conjunction with the hot air blowers and olfactory emitters to suggest the alien's tongue was licking the guest's head.

The special effects in Alien Encounter were so convincing that they contributed to the eventual closing of the show. Even though parents were warned not to bring young children, many ignored the warning and inevitably, terrified, screaming children had to be escorted out of practically every show. Plans to open another version at Disneyland were scrapped.

The acoustics of Alien were complex. Since the seats were moved using hydraulic actuators there were high pressure lines running throughout the theater. The pumps attached to these lines sent high pitched squealing sounds along the pipes and into the set pieces at points of contact. After considerable research we located pipe dampeners, which removed the high pressure pulses being transmitted down the pipes. This, along with careful attachment details, reduced the noise to an acceptable level.