
When the 1979 science-fiction horror film "Alien" first hit theaters, moviegoers had no idea what the creature -- the central character to the film -- would look like.

Above, H.R. Giger with the alien costume from "Alien." The film set the standard for how both science-fiction and horror movies would depict extraterrestrial creatures. But why do different aliens look the way they do? And what will they look like in 20 years?

The "Star Trek" series depicted aliens of all shapes and sizes. Pictured are make-up masks from "Star Trek: The Next Generation" designed by Michael Westmore.

"The eyes and mouth are the communicative windows between the aliens and the humans," makeup artist Michael Westmore says.

The introduction of large oval-eyed "grey" aliens pointed to a change in depiction influenced by both true believers and filmmakers such as Steven Spielberg. Above is an illustration by "Flying Saucers Are Real!" published by Anthology Editions.

The depiction of tentacled extraterrestrials (above) in the recent science-fiction film, "Arrival, "indicates a divergence from aliens reported by supposed eyewitness accounts.

Due to the cyclical depiction of extraterrestrials in films, the portrayal of aliens in films decades from now may not look too different from what we are seeing today. Above, makeup artists work on a character appearing in season 11 of Syfy's "Face Off" show.


