Nightmare Fuel / The Binding of Isaac

Say hello to The Husk, one of the new bosses in Wrath of the Lamb!
We don't have high octane nightmare fuel on this one.
Simply saying "ALL OF IT" will suffice.
-A troper on the discussion page.

Indeed, for a game whose basic premise is a mother trying to kill her son, The Binding of Isaac is pretty unsettling.

However, a lot of the game's horror can count as Tear Jerker. Isaac is abused and destitute, always unloved, always hated, in a house with an overly religious — and also homicidally, sociopathically insane — mother who hears voices. Oh, and the gateway to the Underworld is underneath his house filled with undead or otherwise demonic abominations of all kinds, that also adds a little bit to it.
  • The designs for bosses in Wrath of the Lamb are horrifying. The new bosses seem to be the old ones... After you killed them. Most of them look absolutely horrible, Peep looks the worst by far. He seems to have collapsed on the inside and is bleeding from his eyesockets. Here is the poster.
  • The freakin' trailer. If the enemies looked creepy in 2D, imagine how horrifying they are in 3D! Or, don't imagine anything and just see it for yourself... If you dare.
    • The teaser for the remake is even worse - now everything is not only 3D, but creepy, rubbery puppets: Link Here. Their use of a photorealistic cat's head for Guppy's severed head is jarring and somehow adds a surreal edge to the horror.
    • And now we have the very NSFW release date trailer for Rebirth. Sweet dreams!
  • The tune that plays on the credits after defeating the true form of Womb's / Utero's boss. It comes as a great surprise because it replaces the BGM that usually plays on that sequence... And it's creepy as hell! Made worse by the fact that it's called "Jesus Loves Me." And some speculate that it's Isaac who sings it before suffocating in the Chest!
  • The Halloween update included a new level, Sheol. Which, to quote The Other Wiki, is: "The earliest conception of the afterlife in the Jewish scriptures. A place of darkness to which all dead go, regardless of the moral choices made in life, and where they are 'removed from the light of God'". You know, just in case this game wasn't dark enough!
  • The secret boss of the Halloween update. What appears to be the Headless Horseman, represented as a jawless rotted head charging about the screen while its body acts like the second phase of Pestilence.
  • The True Final Boss of Sheol simply smiles before fighting you. It's unnerving.
  • The fight against Mom, in particular her repeated calls of "Iiii-saac..."
  • ??? / Bluebaby is implied to be Isaac after having locked himself in a treasure chest during a psychotic episode.
  • Similarly: ??? / Bluebaby is speculated by fans to be Isaac or one of his siblings that died before birth and as a result is stillborn, hence the X'd out eyes and the blue appearance. "Blue baby" refers to the fact that it never took its first breath and is just a lifeless corpse roaming around, which is why he has soul hearts instead of regular health. He was never alive to have a beating heart in the first place...
  • The "shopkeeper", a dried-out, eyeless corpse hanging by his neck from a rope, which would imply he committed suicide.
    • That sure still doesn't stop him from taking the pennies off you whenever you buy something. Maybe he is unable to die altogether...
      • If that's true, then what about the times where he lacks a head?
      • Additional Paranoia Fuel — note the fact that when you fight Greed, he has a noose around his neck — one of these cadaverous shopkeepers got so mad or bored that he cut himself down and now wants to kill his customers. Now think that any single one of those shopkeepers could be him before you enter...
      • Take note of where you fight him. In secret rooms... and in shops.
  • Imagine your head being slowly transformed into a tumorous mass filled with flies, all while still conscious. You'll want to put those poor Mulligans and Hives out of their misery as quickly as possible.
    • And The Wrath of the Lamb? Has an upgrade that turns you into one.
    • Also from Wrath of the Lamb - The ones that have bombs painfully wedged into their skull and forced to charge at the player. Just imagine it for a second - Imagine you got possessed and used as a completely unwilling Action Bomb.
  • It is implied that a lot of the monsters are Isaac's lost siblings. How the hell did they end up so horribly disfigured and WHY are they there?
    • Well, considering the things that appear IN HIS MOTHER'S WOMB and in the general areas of the basement: maggots, mutated flies, what is most likely a nest of aggressive parasites, the devil, evil arcana, blood all over the place, Isaac's mother, the karaken, a daedric prince, and randomly appearing flames, it seems likely that Isaac was either the firstborn and other kids came after the problems, or Isaac is just as tough as the person who defeated a knife wielding maniac with no weapons.
    • Word Of God is that the monsters aren't Isaac's siblings, but Isaac himself. Somehow this is worse.
  • Not even the game's soundtrack is immune to Nightmare Fuel, even if it does often cross into Crowning Music of Awesome. But probably the biggest offender so far would have to be Apostate. If anything, this track just goes to show you how really alone you are. It also doesn't help that this is the theme to Mom's womb.
  • Many of the items Isaac can collect are extremely useful, but many carry a high cost in Body Horror or life energy/soul. Some of the worst are actually the most useful:
  • Most of the bugs of the game just fiddle with mook and boss behaviour, or lock you out of certain things. Some other bugs, however, are genuinely terrifying. One of the most persistent bugs happens after clearing a level, when, after the game apparently freezing, replaces the bad dream intermission scene with a version completely in black and white, a la Sin City. Guaranteed to make you defecate bricks the first time you see it. Even more disturbingly still, no one really knows if it is a bug, an intentional feature, or both.
    • Glitched Isaac. Before it was fixed, it could pop up after blowing up a blue rock. It's a copy of Isaac, riding a pony, inside of a Book of Shadows's shield. It floated around the room, and its body contorted and spun at lighting speeds while its head stared constantly at the camera. And besides that, it did absolutely nothing.
  • In many of the secret rooms that you either find randomly from an explosive enemy or through a power-up, you'll find a single, desiccating corpse with a fly or two. In front of the corpse is sometimes a pile of coins, sometimes another power-up, but all the corpse does is sit there, rotting. Did he die from being walled up in Mom's basement? Is he the remains of one of Isaac's attempts at escape? What's worse, sometimes the corpse has no face.
    • Since he looks similar to the shopkeeper (sans noose) and since you fight greed in the shops and in the secret rooms, the person sitting in the secret rooms is speculated to be the shopkeeper/ greed, if not yet another version of Isaac himself.
  • There's a new boss in The Womb/Utero called Teratoma. Wait, what does Teratoma me- OH, SOMEONE TAKE IT AWAY!
    • For those who don't want to follow the link, a teratoma is a tumor with teeth, eyes, arms, legs, and maybe even internal organs. Oh, and they're generally there from birth. And the Teratoma is in the Womb...
      • Also? The Teratoma in Isaac is FILLED WITH SPIDERS. Think about that.
  • The advert for the "Rebirth" expansion serves up Nightmare fuel hand over fist, what with the distorted music, flashing staticky backgrounds, masked nude figures and reverb-y, demonic-sounding singing.
  • The new song for Sheol... is this. It is fucking DEMONIC.
  • You thought Duress was bad enough? well, try listening to it on SLOW FUCKING MOTION
    • And then there's the slow-motion versions of Ascension (2:03:10) and Everlasting Hymn (1:16:45). The Ominous Latin Chanting goes right past "Ominous" into striaght-up hellish.
  • Rebirth brings us this beautiful thing, The Lamb. Just look at it!
  • From The Depths onward, occasionally you may hear Mom laughing from somewhere within the area. You'll then be assaulted by a pair of disembodied hands, presumably belonging to her, Wallmaster style.
  • The spinning disembodied heads in the Womb. They're a crying face orbiting around a lump of meat that slowly edges towards you.
  • Isaac transforming into a demon in the final ending sounds awesome, right? It's not.
  • End2 in Rebirth shows Isaac finding the Rubber Cement... and then he turns to the camera, with his eyes a horrifying milky white, as a Scare Chord plays.
    • Many of the endings in Rebirth are noticeably Darker and Edgier than they were in the first game, ending 3 and 5 like the ones in the first game have Isaac hanging himself and his mom's arm dragging him into the chest respectively but we also have beauties like ending four where Isaac obtains the Wire Coat Hanger, soon finding it lodged in his head, ending 6 which has the poor boy getting sick due to the Ipecac and blowing himself up when he barfs in the chest, and ending 7 which he finds the "Experimental" Treatment, which leaves him horrifically disfigured and mutated.
  • In Rebirth, pretty much everything about End 16! That breathing will haunt you for life...
  • In Rebirth, the beginning of the fights with Satan and Mega Satan are silent except for the blowing wind. For the former, you wait a couple of seconds before fighting the Fallen. for the latter, you walk to a star in the center of the room. At that point, it starts spinning into a pentagram, Satan's battle theme starts playing, and Mega Satan materializes out of nowhere.
  • This track for the Dark Room
  • Also the nauseating Womb track
  • From Afterbirth, Hush, the bonus boss found after beating Mom's Heart/It Lives in less than thirty minutes. It's first form looks like a decomposing Blue Baby/???. Defeating this form reveals the real Hush, a gigantic mass of blue flesh. It has bullet patterns unlike any other boss, able to wrap bullets around the edges of the screen. And when you deplete it's massive health pool and finally kill the damned thing, it's face scorches into the ground.
  • If you thought The Womb was gross and creepy, wait until you see the new alternate version in Afterbirth, the Scarred Womb. It looks like someone took a chainsaw to the inside. The stage theme, while significantly less fleshy-sounding, is still oppressively dark. And then there's the fourth variation, ??? (referred to by players as the Blue Womb) where the aforementioned Hush is fought. While the Scarred Womb was pretty gross, the Blue Womb is just...dead.
  • Ending 17. Isaac's mother enters his room and finds his skeletal remains in the chest. Adult Fear in its purest form. Then there's Isaac's shadow turning into a demonic creature with red eyes and a Slasher Smile...