Nintendo fans who grew up in the '90s likely have memories of offputting encounters in some of their favorite non-horror games; from the battle against Giygas in Earthbound to the man-eating piano in Super Mario 64, old-school games often had an odd penchant for horror despite appearances.

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In the modern era, horror in gaming is nowhere as niche as it once was, but that hasn't stopped it from creeping into non-horror titles. Scares are subjective, of course, but these encounters likely caught everyone off-guard.

Super Mario Galaxy 2: Hell Valley Sky Trees

A screenshot of the Hell Valley Sky Trees from Super Mario Galaxy 2.

Perhaps the second most infamous inclusion in a Mario game behind the possessed piano lying in wait in Super Mario 64 as a hidden detail, the Hell Valley Sky Trees are a quintuplet of black figures which loom far in the distance in Super Mario Galaxy 2's Shiverburn Galaxy.

The name likely hints at the galaxy being referred to as "Hell Valley" during development, though it doesn't shed any light on why the asset was included in the first place. Only visible to those deliberately looking for them, this is certainly one of the eeriest things ever to crop up in a Mario game.

Grand Theft Auto V: The Ghost Of Mount Gordo

A screenshot of an easter egg in Grand Theft Auto 5.

Found in the northeastern part of Blaine County in Grand Theft Auto V, The Ghost of Mount Gordo can be spotted atop the titular mountain between eleven at night and midnight. Said to be the deceased wife of a politician mentioned briefly in the game's lore, she bears a striking resemblance to Samara Morgan from 2002's The Ring.

While most who come across this phantom likely looked up how to find it, those unfortunate souls who stumble upon it organically likely received the shock of their lives. It's definitely not the sort of thing gamers would expect to find in a Grand Theft Auto installment and makes for an alarming easter egg.

BioShock Infinite: Boy of Silence

A screenshot of the Boy of Silence, an enemy from the video game Bioshock Infinite.

While the original BioShock and its direct sequel were heralded as exemplary seventh-generation horror titles, BioShock Infinite, though still a critically-lauded experience, took a slightly different approach. Infinite abandoned the out-and-out horror aesthetics of the original, placing more of an emphasis on high-octane action.

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It still had a few tricks up its sleeve, however. Encountered very late in the game, the Boy of Silence is a horrendous watchman encountered in Comstock House who is able to pick up on introducers via a keen sense of hearing. Just before Booker escapes the area, he's jump-scared by one of these gnarly guardians, making for a breathtakingly baleful moment.

Dark Souls III: High Lord Wolnir's Reveal

A screenshot of High Lord Wolnir, a boss form Dark Souls 3.

Despite its dark fantasy setting, the Dark Souls series rarely dabbles in outright horror. Bosses such as the Gaping Dragon from the first installment and the Flexile Sentry from the second border on it, but Dark Souls 3 goes so far as to introduce a boss via a jumpscare.

Encountered during the climax of the Catacombs of Carthus area, after interacting with an ominous chalice, the player is taken to a black void where they stumble upon the skeletal scion. While not quite as grotesque as some of the series' other bosses, High Lord Wolnir's sudden, terrifying entrance makes him memorable.

Fallout 4: The Dunwich Borers

A screenshot from the Dunwich Borers questline in Fallout 4.

The Fallout series is best-known for its atompunk aesthetic and post-apocalyptic pandemonium, but it often includes a cosmic horror bent on which less inquisitive players may miss out. Fallout 3 featured the Dunwich building, a reference to H. P. Lovecraft's The Dunwich Horror, and Fallout 4 took things a step further with the Dunwich Borers.

A quarry heavily defended by raiders located in the northeastern corner of the map, those who venture into the excavation site discover that some strange entity is wreaking havoc. Many Fallout hidden quests include elements of horror, and this is a sterling example of that.

Red Dead Redemption 2: Butcher Creek

A screenshot of the Butcher Creep pentagram from Red Dead Redemption 2.

When camping in Roanoke in Red Dead Redemption 2, it's possible to encounter a deranged woman who speaks of a cursed village known as Butcher Creek. Following the Wisdom of the Elders questline will allow players to unravel the mystery surrounding the place which involves a charlatan shaman exploiting a town that's apparently being affected by water tainted with lead and arsenic.

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However, one abandoned shack in the village hides a glowing pentagram that can be seen from four to five in the morning. The implication here seems to be that the residents of Butcher Creek really are being haunted by a demonic force.

Call of Duty WWII: Panzermörder Reveal

The Panzermorder boss from Call of Duty WWII's Zombies mode.

Call of Duty's Zombies mode, first introduced in 2008's World at War, had developed into a staple of the series by the mid-2010s. Unfortunately, after multiple iterations, the mode was in danger of jumping the shark. In response, Call of Duty WWII developer Sledgehammer Games opted to return the Zombies mode to its roots.

The Final Reich was a relatively grounded launch map that felt like a major departure from Call of Duty: Infinite Warfare's Zombies in Spaceland saga. Full of jumpscares and other horrific moments, the pinnacle of the experience likely came at the culmination of the map's Easter egg quest which saw players do battle against a body-horror-inspired amalgamation of corpses known as The Panermörder.

Subnautica: The Ghost Leviathan

A screenshot of a Ghost Leviathan in the survival video game Subnautica.

The second-largest hostile entity in the game, The Ghost Leviathan is a harbinger of death from which most Subnautica players will be keen to stay far away. Typically encountered in the Crater Edge, they serve as a way to cause players who've ventured too far out into the abyss to return to the game world.

While Subnatuica can be a beautiful and at times serene experience, players who dare to push their limits are bound to come face to face with one of these monstrosities. Titanic, translucent, and able to emit a banshee-like scream, these are without a doubt the most unpleasant forms of aquatic life found in Subnatuica's vast ocean.

Undertale: The True Lab

A screenshot of the True Lab from the video game Undertale.

An unabashed love letter to the Mother RPG series, Toby Fox's Undertale is a weird and wonderful adventure full of humor, intrigue, and open-ended adventure. On that note, should the player make an effort to spare all of their enemies and fulfill a handful of other requirements, they'll gain access to the True Lab, the secret den of the bashful scientist Alphys.

It turns out that Alphys orchestrated an experiment intended to revive the dead, but her test subjects morphed into body-horror abominations known as Amalgamates. It's a weird, disturbing twist made all the more uncomfortable by the happy-go-lucky nature of the rest of the game.

Spec Ops The Line: White Phosphorous Incident

A screenshot from the video game Spec Ops: The Line.

A twisted tale heavily inspired by the 1979 film Apocalypse Now, Spec Ops: The Line sees a group of three soldiers attempt to put an end to a rebel militia causing chaos in a devastated Dubai. All is not as it seems, however, and the lines between truth and falsehood become increasingly blurred as the game goes on.

Early on, the three believe they've stumbled upon an enemy encampment and utilize white phosphorus to clear it out. However, in a shocking twist, it's revealed that they actually conducted a chemical attack on a refugee camp. This traumatic incident serves as the linchpin around which the rest of the warped narrative is held.

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