Warning: Seriously creepy spoilers for Bird Box ahead!
You probably won't be even halfway through Bird Box before you find yourself wondering two questions: what, exactly, are the mysterious creatures trying to kill Sandra Bullock? And what the hell do they look like?!
If you've watched Netflix's sci-fi thriller, then you know the answer to those questions remains a mystery. Sure, our heroine, Malorie (Bullock), might safely make it to a refuge after navigating a few days down a river while blindfolded, but where the creatures came from, what they look like, and if they'll ever be defeated is left ambiguous. However, thanks to one scene featuring a particularly creepy character, we have a hint as to how the creatures might present themselves.
In Netflix's official summary of the film, the monster is referred to as "a mysterious force" that "decimates the world's population." The so-called entity does so by making whoever lays eyes on it commit suicide pretty much instantaneously in the most graphic way they can manage (caving their head in on the corner of a desk, walking in front of a dump truck, lighting themselves on fire, etc.). The only way Malorie and her fellow survivors are able to escape its influence is by making their way through the world blindfolded.
But then a surprising new threat emerges: homicidal people who are driven crazy by the creatures, but who somehow avoid those pesky suicidal urges. Gary, played by Bohemian Rhapsody's Tom Hollander, arrives at the sprawling home where Malorie and the rest of the survivors are staying, banging at the door and begging to be let in. Sweet-natured Olympia (Danielle Macdonald) opens the door for him without consulting anyone else, and at first, it seems like Gary will be a fine addition to the crew (despite Douglas's very loud objections). However, before long, it's revealed that Gary is one of the few human beings out there who can survive after seeing the monsters.
Why is that? Well, it's not clear. We get hints that some of the people who can look at the creatures and not commit suicide suffered from mental illness before the monsters arrived (Gary mentions that he was institutionalized). That doesn't mean they get off scot-free, though — rather than killing themselves, they begin zealously worshiping the creatures and try to force other survivors to "look" at them and join the cause (or kill themselves, whichever).
But Gary's arrival at the house is also the only clue we get about what the creatures might look like, at least to him; he comes equipped with a folder full of charcoal drawings of blurry monsters with screaming mouths full of razor-sharp teeth, black eyes, bug-like appendages, and even one that appears to be wearing a gas mask. Essentially, they look like demons.
We never actually witness what Gary and others like him see, but there are a few clues that suggest the creatures either present themselves to regular people as a person's ultimate sadness or fear. For instance, after Malorie's sister, Jessica (Paulson), sees a creature while driving, her eyes immediately flood with tears and she crashes the car. Then she promptly limps out in front of a garbage truck to end her life.
Something similar happens to the wife of Douglas, John Malkovich's character, when she runs outside to help a wounded, pregnant Malorie. "Mom?" she asks, staring at empty air, before her eyes blossom into a creepy, bloodshot kaleidoscope of oranges and browns (aka what happens to all the eyes of people who "look"), and she willingly climbs inside a burning car. Douglas later tells Malorie that her mother has been dead for years.
While it's pretty obvious that not all the creatures present themselves the same way to people (ex: Douglas's wife seeing the image of her dead mother), Gary's rendering of them might be the closest thing we have to seeing their true form.