Look closely and you'll spot The Haunting of Hill House ghosts hiding in the background of every single episode. It's... just a tad creepy. According to an interview with Vulture, showrunner Mike Flanagan said that they “hid dozens of ghosts throughout the series, in plain sight, in the deep background of shots... if you look in a door frame, or under the piano, or behind a curtain in a lot of otherwise ordinary scenes, you’ll see someone there”.
He’s not kidding. You might not have noticed the first time you watched the show, but there's ghosts hidden throughout the series and most of the time they're not even part of the wider story. If you're curious to find out how many you spotted and when and where they appear in the show, here's every hidden Haunting of Hill House ghost we've spotted in the Netflix Original so far, in episodic order. Just try not to get freaked out too badly by their pale, drawn faces, ok?
Finished the spooky series? Read up on The Haunting of Hill House ending and find out everything you need to know after watching.