The point of horror movies is to scare the audience, and it's possible to do so without displaying the antagonist in question whatsoever. In fact, it can be argued that not being able to visualize the threat makes them far more dangerous (and, therefore, significantly more thrilling for viewers).
While this doesn't take away from films that reveal the sources of conflict (whether human, animal, or supernatural), the reason that darkness is so terrifying is because it is the unknown - an infinite and empty container. Anything can be hidden outside our line of sight, turning personal safety into a game of chance.
10 His House (2020) — The Apeth Is Vengeance Given Form And Power
His House is all about the horrors of war, revealing the extent that people go to in order to save themselves and their loved ones. Rial and Bol manage to escape South Sudan with Nyagak, their daughter, who unfortunately drowns in the English Channel.
Her parents are forced to live like second-class citizens in the UK and are haunted by the ghosts of their past. This supernatural entity, referred to as an "apeth," is a grotesque misshapen creature, but it's not a threat as much as an attempt at righting a moral imbalance.
9 Paranormal Activity (2007) — The Demon Appears In A Split-Second Frame At The End
Paranormal Activity revolves around Micah, Katie, and a spirit that has plagued the former for most of her life. This demon reveals its presence through sound, electricity, and furniture motions, eventually taking control of Katie.
Micah tries to help as best as he can, but his partner refuses to listen to reason, behaving more and more strangely with each passing night. The demon wins in the end, forcing Katie to murder Micah, only revealing itself in a split-second frame before the movie cuts to black.
8 The Witch (2015) — The Real Horror Comes From The Family's Emotional Collapse
Thomasin traverses a complex terrain in The Witch. She is indirectly punished when her family is exiled for her father's beliefs and later bears the brunt for "misplacing" her baby brother, Samuel. There are witches that pop in and out of the movie, appearing in brief flashes as well as in the ending.
However, none of the characters are killed by actual villains, perhaps excluding William's death at the hooves of Black Phillip, who later transforms into a mysterious man (who might be in Thomasin's head). The real horror in this film comes from the family's psychological collapse.
7 Bird Box (2018) — The Story Allows Its Characters, But Not The Audience, To See The Threat
The world is haunted by an unknown entity that somehow forces anyone who sees it to commit suicide. Malorie Hayes finds temporary respite in a nearby house, an experience that gradually turns utterly terrifying.
Bird Box shifts its narrative to half a decade into the future, showing Malorie, Tom, "Boy," and "Girl," living together as a family. The movie subverts a basic horror trope by allowing its characters (but not the audience) visual access to the threat.
6 Under The Shadow (2016) — The Djinn Takes The Form Of An Endless Piece Of Fabric
Shideh inadvertently allows a Djinn to wreak havoc on her life, a problem compounded by the other issues in her life - her husband's absence and rampant sexism in '90s Iran, just to name a few.
She wants to protect her daughter Dorsa from both the evil entity and society's expectations of women, although it's not really clear if she succeeds by the end of Under the Shadow. The Djinn appears in its traditional form, an endless piece of fabric that comes alive in the billowing wind.
5 Gerald's Game (2017) — Jessie's Hallucination Is A Lot Scarier Than The Truth
Gerald believes that subjecting Jessie to a bizarre sexual fantasy is the path to strengthening their fading relationship, erupting in a rage when she begins resisting his advances.
Gerald is subsequently killed by an unexpected heart attack, leaving Jessie to spend the next few days hallucinating everything under the sun, from her husband's reincarnation to the "moonlight man." The latter is revealed to be a serial killer at the conclusion of Gerald's Game, but he never had any intention of hurting Jessie.
4 Oculus (2013) — The Villain Is An Innocent-Looking Antique Mirror
The antagonist in Oculus is an antique mirror that supposedly manipulates and deceives those who peer into its dusty silver gaze.
It causes the Russell family to devolve into states of varying frenzy, indirectly killing both Marie and Alan (the parents). Ten years later, the two kids, Tim and Kaylie, try to uncover the mirror's secrets, only to be foiled at every turn. Oculus is another horror movie where the invisible villain wins.
3 Hereditary (2018) — Paimon Eventually Manifests Himself Through Peter
The Graham family is shattered when the 13-year-old Charlie is gruesomely killed in a car accident. Her brother Peter blames himself for his role in her death. Annie desperately wants to contact her daughter, performing a séance that results in more supernatural trouble than expected.
The story eventually leads to Paimon, a demon-king who possesses Annie and forces her to attack her son. Peter then becomes the entity's host and undergoes an eerie coronation ceremony. Hereditary is a visceral experience through and through.
2 The Mist (2007) — The Story Proves That Being Present Is Not The Same As Being Accounted For
The Mist reveals how much people depend on the sense of sight, throwing its villains into a thick fog blanketing the entire town of Bridgton, Maine.
Monsters from arachnid mutations to deformed insects surround the supermarket containing the movie's main cast, but the lack of visibility impedes both reaction time and levels of survivor knowledge. The Mist proves that being present is not the same as being accounted for, a philosophy applied to heroes and villains equally.
1 It Follows (2014) — The Entity Takes On Different Forms, Including Those Of Victims
Hugh has sex with Jaime before informing her that she will now be followed and haunted by a demonic creature that can be foisted on other people through coitus. Jaime begins visualizing suspicious characters all around her, none of whom can be perceived by anyone else.
Greg has sex with Jaime since he refuses to accept that such a thing is possible, which obviously results in his violent murder. In It Follows, the demon takes different forms, including those of its would-be victims.