The world’s first science-fiction tale started with a dare. Stranded by bad weather in Switzerland, Mary Shelley, her poet husband, Percy and their friends vied to see who could come up with the best horror story.

Clearly, Shelley won.

“Frankenstein; or, The Modern Prometheus” came to her in what she later called a waking dream: a vision of a pale man leaning over the creature he’d put together. Published in 1818, that story has haunted the public’s imagination ever since.

Now it’s lumbered into the Morgan Library & Museum in the form of “It’s Alive! Frankenstein at 200,” a (monster) mashup of paintings, posters, manuscripts, movie stills, clips, comic books and more, divided into two galleries — what came before, and what surfaced after.

In the hall between the two is what co-curator John Bidwell considers the centerpiece of the exhibition: a portrait of Shelley painted in 1840, long after she’d lost both a baby and her husband. She has a Mona Lisa-like smile and eyes that seem to be on you as you scroll through her annotated manuscript on a nearby screen.

Some of her handwritten pages are here, too, with Percy’s notes scribbled in the margins. And while we think of the monster as a monosyllabic hulk — he was played by mimes on the London stage a few years after the book came out — he was actually pretty eloquent, quoting Milton’s “Paradise Lost”: “Am I Adam? Or am I Satan?”

As far as most of us are concerned, he was Boris Karloff, the star of 1931’s “Frankenstein.” A production photo shows him with Marilyn Harris, who played the girl the monster hurls into the river. The text block tells us that little Marilyn’s mother was on the set that day, yelling, “Throw her in again! Farther!”

Walls full of B-movie posters show just how adaptable Shelley’s story is. Everyone from Abbott and Costello to Andy Warhol took a whack at it, while Ed Wood’s “Bride of the Monster” cemented his reputation as the worst director of all time — maybe because the “monster” in his movie was … an octopus.

“It’s Alive!” runs through Jan. 27 at the Morgan Library & Museum, 225 Madison Ave.; TheMorgan.org