Disneyland turned their Mission to Mars location into a pizza restaurant
after Alien Encounter at The Magic Kingdom didn't go over with guests
as well as they expected.
During the 1994 redo of The Magic Kingdom's Tomorrowland, several
new attractions were added including The ExtraTERRORestrial Alien
Encounter. Located in the show building of the closed Mission to
Mars, this attraction made use of 3-D sound techniques Disney has
used earlier at the Disney/MGM Studios. And more.
George Lucas and Disney worked together to create a very scary
(and un-Disney like) thrill show.
Trivia: Yes, that's Tim Curry as the voice of S.I.R. in
the preshow. The original voice was done by Phil Hartman in a much
more comical style. After a short time, the original version was
closed and redone to make it more spooky.
Trivia: Originally, this attraction was going to use the
alien from the movie Alien. Before this, there were plans to build
a ride through attraction based on Alien which would let guests
shoot "lasers" at alien targets during the ride (or, perhaps,
using the ride system for a Dick Tracy themed attraction). Eventually
this concept surfaced as the Buzz Lightyear spin ride at TMK.