You can now be the proud owner of the utterly petrifying ‘Alien’ costume

It terrorized the inhabitants of Sigourney Weaver’s spaceship in the 1979 sci-fi flick “Alien” – and now the salivating extraterrestrial can bring mayhem and horror into your home, too.

In honor of so-called “Alien” Day, April 26, Julien’s Auctions in Beverly Hills is accepting bids on a translucent prototype costume of Big Chap, as fans call the titular Xenomorph.

The unofficial holiday is inspired by the name of the moon that Big Chap lives on — LV-426, hence 4/26 — where human crew members including Weaver, Harry Dean Stanton, Ian Holm and John Hurt (of exploding-stomach fame) touch down in the Oscar-winning Ridley Scott movie.

Even though the prototype did not end up in the actual film — Scott opted for a subsequent, more opaque version — die-hard fans are clamoring to buy the full-size earlier model designed by surrealist Swiss artist and sculptor H.R. Giger.

The specimen is expected to fetch between $40,000 and $60,000.

“[It] remains Giger’s true and original vision of one of the most significant and iconic science fiction monsters of all time,” said Martin Dolan, executive director of Julien’s. “This is the first opportunity for the public to have a chance to own what may be H.R. Giger’s most important work, more than four decades after its creation.”

The veiny prototype — which includes a complex mouth-breathing apparatus on its back — was designed to be worn by the 6-foot-10 Nigerian visual artist Bolaji Badejo, cast as the alien for his exceptionally long legs.

The costume’s lips were made from latex condoms, while the final interpretation incorporated real human bones, including a skull inside its cylindrical head.

For scaredy-cats who reckon Big Chap is too grotesque for their tastes, a number of less alarming items are also going under the hammer from the “Alien” franchise. They include the flight suits worn by Weaver and Winona Ryder in 1997’s “Alien: Resurrection.”

Among the other sci-fi lots offered in the same “Hollywood Sci-Fi, Action, Fantasy and More” auction are the jet-pilot outfit worn by Will Smith in the 1996 film “Independence Day,” the original space dock (with lights!) from 1979’s “Star Trek: The Motion Picture” and an authentic Imperial scout trooper “biker scout” blaster used in “Return of The Jedi” in 1983.