The monsters in Bird Box are currently the film’s biggest mystery, and not showing them off to viewers is generally considered the movie’s biggest “mistake” - but, in reality, keeping the monsters hidden is why it’s actually great. Instead of releasing another big winter movie over Christmas weekend, Netflix opted to provide subscribers with a thriller to keep them on their toes throughout the rest of the holiday season. And, so far, it’s been quite the smashing success.

Starring Sandra Bullock, Trevante Rhodes, Rosa Salazar, and more, Bird Box is a post-apocalyptic thriller directed by Susanne Bier and based on the novel of the same name by Josh Malerman, which takes place in two time periods - immediately after society’s collapse and then five years later. Centering on Malorie and her two children - Boy and Girl - Bird Box’s basic premise is that there are now monsters in the world, and looking at the monsters will force someone to kill themselves.

Considering Bird Box’s story is about monsters that prey people’s senses - in this case, sight - the film has obviously drawn comparisons to this year’s A Quiet Place, which is another post-apocalyptic thriller that has monsters preying on people’s senses. But among the numerous differences between the two films, one of the biggest differences is that Bird Box holds back its monsters. Whereas A Quiet Place’s monsters are quite prominent, Bird Box refrains from ever showing (or even describing) its monsters.

Not showing Bird Box’s monsters has been considered the film’s biggest “mistake,” but in addition to setting it apart, could it actually be one of its greatest strengths? Compared to the general conception of monsters, which are typically creatures that inflict physical harm on individuals, Bird Box’s “monsters” are more psychological in nature. Based on what was revealed in the film, everyone who sees the monsters sees something different, and not everyone who looks at them dies immediately. While there are several supporting characters in the film, audiences experience the story through the eyes of the main character, Malorie.

Since she survives the film and doesn’t “see” the monsters herself, then it makes sense that viewers wouldn’t either. After all, revealing them would mean that she or one of the children would probably die. Instead, audiences see how the monsters affect the environment, particularly the Earth’s gravity. Interestingly, there are moments in the film in which audiences do get a sense of what the monsters may look like; first, by seeing a silhouette of a creature walking by the house at night and, second, through Gary’s (Tom Hollander) sketches that he lays out on the table.

For the purpose of Bird Box, that’s all viewers need to see in order to understand that there are monsters in the world now. Choosing to not show the monsters is a great decision because it not only keeps the mystery alive but also works quite well in the overarching narrative about sight equaling death. Plus, sometimes revealing the monsters in movies like this can be anticlimactic, and since each monster is supposedly different in Bird Box, it seems the filmmakers made the right choice by hiding them away.

More: Bird Box’s Ending & Monsters Explained