It pulsates until a facehugger bursts from within to, well, live up to its name.

It’s the stuff of nightmares.

“It’s like a hot cross bun,” the Oscar winner tells EW, laughing.

On the Set of “Alien”

Credit: Sunset Boulevard/Corbis via Getty Images

Then again, he has a point.

Designed by the celebrated Swiss painterH.R.

But the eggs weren’t just unsettling for the way they blossomed rather than hatched.

ALIEN, 1979, TM

Everett Collection

The one Kane approaches known as the “hero egg” on set had innards that throbbed.

“He just put his hand in there and pushed up, and there it was.

It looked gross, but it lookedreal.

ALIEN

Everett Collection

[The eggs] looked beautiful, really.

And Ridley added smoke to soften the atmosphere.”

Speaking of which, that smoke had an unusual source of inspiration: the Who.

“I said, ‘We gotta get Ridley in here,'” Christian recalls.

They thought maybe we could animate it afterwards….

So this was sheer luck, that I’d gone up to see the Who."

And that wasn’t the only happy accident contributing toAlien’s success.

Or maybe they just found the image scary because, as harmless as they seem, eggscanbe scary.

And then it created many more.

A version of this story appears in the new issue ofEntertainment Weekly, on stands now orbuy it here.