One of the cast members of Netflix's addictive horror series "The Haunting of Hill House" is talking about a tiny detail that might completely change our interpretation of the ending.

WARNING: MAJOR SPOILERS if you haven't finished watching the show.

Oliver Jackson-Cohen, who plays struggling addict Luke, made an eerie observation to The Wrap: In the final episode, whenever we see red in a scene where something usually isn't red, that means the characters are still in the Red Room. For example, Luke is usually wearing black Converse, but in the hotel room with his fellow addict, his shoes are now red. Sure enough, that was all a fantasy (or nightmare).

But what does it mean in the very final shot -- where everyone is celebrating Luke's 2 years of sobriety -- that the cake is red? Does that mean that this is also a fantasy? That Luke really did die in the Red Room?

If you found the ending too upbeat -- including Steve (Michiel Huisman) being back with his wife and (somehow) about to become a father -- then this darker twist might make more sense. Especially since the final episode began with exactly the kind of too-happy fake-out we see in the last shot.

It was actually Kate Siegel (grown-up Theo, who's also married to the show's creator, Mike Flanagan) who pointed it out to Jackson-Cohen. "Um, she went, ‘The cake is red," he recalled. "And on set I went, 'Oh, my God!’ And she went, 'I don’t know!'"

Jackson-Cohen then asked Flanagan, who also said, "I don't know!" That leaves it up to the actor -- and us -- to decide how to interpret this one tiny detail: "I can't tell whether or not I'm just crazy with this — or whether or not it’s something that could have legs."

Either way, don't expect to see any more of the Crain family.

Flanagan told EW he and the writers “toyed with a cliffhanger ending" to set up a second season. “Ultimately, in the writers’ room and with the cast and everything else, we really felt like the story demanded a certain kind of closure from us and we were happy to close the book on that family," he said.

But was the family happy, Mike? Was the family happy or not?!

[Via The Wrap, EW]