Henry Creel’s Fear of the Cave in ‘Stranger Things’ Explains How He Got His Powers

Spoiler alert: The following contains spoilers for Stranger Things Season 5 and The First Shadow, a stage play written by Kate Tefry, who worked with the Duffer brothers.

When Stranger Things first dropped on Netflix, audiences were captivated by the original series by a perfect storm of artistic decision-making. From an aesthetic and setting standpoint, the showrunners appealed to viewers' sense of nostalgia.

When you combine all of these factors with a writing team skilled at crafting scintillating cliffhangers, you've got a show that makes binge-watching easy. And five seasons in, Stranger Things fans are still left asking questions. Like why is Henry afraid of that cave?

The play The First Shadow features an origin story of sorts that delineates how Henry Creel, aka Vecna, came to gain his psychic abilities.

The First Shadow also features high school versions of Hawkins, Ind., characters featured in the Netflix series, along with a fairly extensive explanation as to why Henry was scared of following Max into the cave. He's such a terrifying and powerful villain, so if he's wary of venturing into an area, it's got to be pretty bad, right?

And the play does a good job of explaining exactly why this is the case. Everyone who's ever watched Stranger Things, and probably folks who haven't, has heard of the Upside Down. Many think that this bizarre dimension is where the horrifying creatures like Demogorgons, Demodogs, the Mind Flayer, and the Flesh Monster live.

However, the Upside Down actually isn't where these beings come from. Instead, they come from a place originally called Dimension X, which is later called the Abyss in Netflix's Stranger Things universe. The Upside Down serves as an interstitial space between the horrifying Abyss and our world on earth.

The First Shadow informs audiences that Creel accessed the Abyss via the cave system he's so leery of. Dr. Brenner, played by Matthew Modine in the show, was running experiments with equipment he acquired from the U.S. military. Brenner's father had entered the Abyss briefly during World War 2, and an American scientist had defected to Russia, bringing some of this interdimensional traveling hardware with him.

As this U.S. soldier was fleeing, he came across Henry Creel, and this military equipment sent the two of them into the Abyss. In the Stranger Things play, Dr. Brenner explains what happened to Henry and the cave during a monologue. This connects to Stranger Things: Season 5 Volume 2, where Max and Holly end up viewing Henry's altercation with the treasonous scientist.

Henry is shot in the hand by the U.S. defector, and he ends up killing the researcher with a rock. Upon doing so, he becomes intrigued with a briefcase the scientist is carrying, which, thanks to the information provided by the play, we know is a conduit that leads Henry directly to Dimension X (the Abyss).

So Henry Creel's (Vecna) fear of that cave in Nevada boils down to that fateful encounter. And his first journey into this horrifying dimension is what's responsible for his powers. Furthermore, The First Shadow features Dr. Brenner telling Henry that when his own father emerged from the Abyss, his blood type had been altered.

The same happened to Henry, and we come to learn that the children being tested on in the Hawkins lab, Eleven included, all received transfusions of Creel's blood. And this is where their powers stem from. So they're able to get the same powers others who've been exposed to the Abyss and creatures like the Mind Flayer receive, without all of the horror of reality-shattering events.