Plankton, in the early seasons, certainly was terrifying. In a series that began with colorful and humorous people, with good intentions and friendly, he stood out to be a very sociopathic character (of course, before its Villain Decay after the movie).
In an episode of the first season, Bob gets to a dream of Plankton, where he is a giant monster, and destroys all Bikini Bottom and presumably killing people. Worse, has a sadistic joy with this dream and nearly crush Gary, just For the Evulz.
Often Mr. Krabs shows a pretty frightening behavior. Sometimes it makes you start to question his mental health, bordering the line that goes from a insane psychopath who would do anything for money or frighten their employees (this is is evident in episodes like "Clams" and "Wet Painters" ), to a Sadist who loves to watch the suffering of others ("Nasty Patty", "No Hat for Pat" and "One Coarse Meal") or just a greedy Jerkass who is willing to do some pretty cruel things to make money ("Jellyfish Hunter" and "The Cent of Money ")
Depending on whom you ask memetic faces are either hilarious or horrifying...
The terrifying-ness of SpongeBob SquarePants is lampshaded in 30 Rock, where after Kenneth gets cable TV for the first time, he remarks "Is SpongeBob SquarePants SUPPOSED to be so terrifying?"
For such a light-hearted series, Dennis (the Bounty Hunter that chases SpongeBob and Patrick throughout the film) is a surprisingly threatening and vicious villain.
The diver probably gave more than a few kids nightmares when he showed up.
Another example is in the video games Battle for Bikini Bottom, and SpongeBob's Truth or Square in Rock Bottom. The music there is HORRIFYING. It's also not helped by the fact, that those Sleepy Robots are both REALLY ANNOYING AND IN THE WAY but also VERY HARD TO KILL!! And it will hurt you very easily. Especially with Sandy. Rock Bottom in BFBB is also one of the most complicated places in the game.
The Kelp Caves. The music is a sluggish, lower version of the regular Kelp Forest music, with added background noises like the noises of cave-dwelling animals. Its combination of eerie setting, disturbing music, and cramped space is disturbing. Not helping is the fact that some get stuck in the cave for literally years before figuring out the solution...the Sleepytime robots are also scary, mainly because of the fact that it makes a loud noise when striking. For some reason, some also find the Monsoon robots scary. Not helping is the fact that one of each can be found in the Kelp Caves...
SpongeBob SquarePants SuperSponge has bosses like the shark sub, sea snake, and bronze dogfish. They're quite scary looking for the overall audience to the series, not to forget the accompanying boss music (Especially in the GBA version).
A lot of episodes feature SpongeBob's brain for some reason, and all of them are extremely creepy. For example: see Plankton, Scaredy Pants, Welcome to the Chum Bucket, Penny Foolish, Bucket Sweet Bucket, and The Inside Job.
Squidward's Suicide, though this is a fan-made episode. Watch the Some Ordinary Gamers video here, if you dare.
Some of SpongeBob's faces belong to the Uncanny Valley side. Patrick's, Squidward's, Sandy's, Plankton's and Mr. Krabs' should be in there too.
There's "Tea At The Treedome", which revolves around Spongebob slowly dehydrating in Sandy's tree dome. The fact that Patrick gets trapped in the treedome towards the end as well doesn't help.
And all the while, he's convincing Sandy that he's fine, and also kinda giving into Patrick's peer pressure, until he can't stand it anymore.
Spongebob's Madness Mantra of "I don't need it" before he finally snaps.
Pretty intense when you realize that all that time he's been slowly suffocating to death.
"Squeaky Boots", which is a parody of The Telltale Heart. Mr. Krabs becomes annoyed by the squeaky sound of these new boots he gave Spongebob, so he steals them and hides them under the floorboard of the Krusty Krab. Back at the Krusty Krab, he has a disturbing hallucination sequence as a result of his guilt, in which he hears the squeaking everywhere and goes mad from it.
Patrick going crazy in "Nature Pants" when he started to miss SpongeBob, who had decided to give up his old life and live among the jellyfish. Especially the scene where he takes a swing at SpongeBob with a jellyfish net, and as an Ominous Music Box Tuneis heard in the background, Patrick tearfully but angrily says "If I can't have you as a friend, I'm gonna make you a trophy!" He then shows SpongeBob a jar with SpongeBob's name on it and tells him "I even picked out this nice jar for you!"
"FRIENDS FOREVER, SPONGEBOB!!!!"
All the chaos caused by the fish trying to 'do the sponge' in "The Chaperone" was really funny, but also kind of disturbing, such as breaking their own legs clean off, getting their bodies and heads swapped with each other, getting chased (for some reason) by a giant apple, and just straight up dying with paramedics catching them on a stretcher!
When SpongeBob wanted to dress as the Flying Dutchman for Halloween, but his square body didn't allow this. Patrick decided to give him a "haircut" for it to fit. It's not until after a botched attempt at a prank that the real Flying Dutchman tells him to take off the sheet, and flies off screaming. The camera then cut to SpongeBob, where it turns out Patrick didn't just cut off his edges, he cut him down to his brain! Everyone else then ran away from them. Patrick doesn't realize why they all ran off at first, but shortly after SpongeBob explains about his brain, Patrick suddenly runs away too. Despite all this, as was pointed out, "Don't worry-- it grows back".
In "I Was A Teenage Gary" SpongeBob turns into a snail after being injected by snail plasma. Naturally, it was quite a painful transformation, and left him unable to talk.
Oh, he talks all right... by meowing. He even gets a deliriously happy grin and blissfully blank eyes. Basically, it's a human being acting like an animal while still sounding human, and it's unsettling.
SpongeBob: I take it back, Gary. Something's wrong with meeeeeeeeeow!
...and the music that plays shortly afterward is absolutely horrifying
There's a deleted scene on the DVD with this episode on it with Squidward transforming into a snail as well.
In "SB-129", Squidward travels through time and ends up in a blank white void. He remarks to himself that he can finally be alone... which is when the word manifests itself as a colorful caption. Then a series of disembodied voices start saying the word "alone", accompanied by more colorful representations of the word, until Squidward finally snaps and tries to get out.
There's also a major Fridge Horror factor to that. Were those voices coming from other people who had been trapped in the same void? Extra Fridge Horror: What if he really is alone?! They may be just projections from the void!
"SB-129" also has a mega case of Fridge Horror. Squidward is in the freezer for 2000 years, and then he gets sent back to the past, and eventually to his own time. Fair enough, right? But then you realise that there are now two Squidwards: the one that returned to the present, and the other which is still STUCK INSIDE THE KRUSTY KRAB'S FREEZER. Presumably it never gets discovered, hence why Squidward isn't freed for 2000 years, which essentially means that after that episode, there's a frozen replica of Squidward inside the freezer. Just as well none of the customers know that...
It kind of gets worse when you realize that in another episode SpongeBob says he checked every freezer in the Krusty Krab. Considering how stupid SpongeBob has been lately, it wouldn't be a shock if he saw the frozen Squidward and did nothing about it.
There is at least one other episode, "Nasty Patty," where the Krusty Krab freezer is seen again, completely empty. But it's funny, in that episode, they were trying to hide a body in there from the police (yeah...); but supposedly at least one body was already inside...
The episode where SpongeBob is trapped overnight in Rock Bottom definitely plays to childhood — and adult — fears.
The things that come out of the bathroom. What makes it scarier is that all of those beings are based on real animals.
The April Fools episode. After one too many a prank by SpongeBob, Squidward sets him up a prank that crosses the line, sending SpongeBob home crying. But that wasn't it. Earlier in the episode, SpongeBob, as part of one of his pranks, pretends to lose his tongue, which turns out to be a fake. But the part that gets scary is that the tongue is alive, laughing cheerfully and innocently with SpongeBob. It's never explainedwhat it/he/whatever is exactly, which makes it a bit creepy.
A lot of that episode went WAY beyond Tear Jerker, and became disturbing. First of all, Squidward laughing like a freaking SADIST as he pranks SpongeBob, who runs off crying. Squidward's hallucinations caused by his own guilt are REALLY unsettling. Especially when he imagines his mother scolding him. (Which becomes Nightmare Retardant when you hear the voice come out of her. "YOU STINK!")
Oh, and Squidward tries to say sorry, but his face turns into a hideous donkey (or ass) for a few seconds. Then he explodes.
"Squid's Day Off" where SpongeBob is left in charge of the Krusty Krab while Squidward goes out to do some "errands". After running back and forth Squidward finally barricades himself in his house. "I'm not going to think about you know who, at the who know what, doing I don't care." Cut to creepy laugh and a psycho looking Squidward with his eyes bloodshot and wide eyed.
The music that plays in the scene mentioned above. It's very demented, creepy music box music. What's even scarier is that no one has found out what the song is called or where to find it!
He gets progressively MORE psycho-looking until he ends up running back to the Krusty Krab with the most horrifying, off-model expression ever seen in SpongeBob.
In the episode "Bubble Buddy", a man asks SpongeBob to bury him in the sand. He does and then asks Bubble Buddy to dig him out and walks away. The tide comes in and we later see him as an angel/ghost.
Also, Bubble Buddy is shown to be fully sentient at the end of the episode, after making the fish experience high tide. So he was sentient the whole time and could have helped the fish, but he just watched the fish drown.
In "Dying For Pie" when Squidward is doing all of the things SpongeBob wanted to do with him, there's a part where SpongeBob is doing surgery on Squidward and poking Squidward's heart while Squidward is still conscious. A few moments later, BLOOD STARTS SQUIRTING OUT.
The entire premise of that episode is nightmare fuel. The concept of a bomb being hidden in food so there is no way to see it or defuse it? Ugh.
Wormy. That must've made some kids develop mottephobia.
Oh god, those live-action bug close-ups were horrible.
"Squid on Strike" ends up with Spongebob and Squidward having to work for Mr. Krabs "FOREVER" by which the next scene shows Spongebob and Squidward as living skeletons having to work there for all eternity. It's played for silliness, but when you dig deep enough that's almost And I Must Scream territory.
"I'm Your Biggest Fanatic" ends with dorky Jellyfish catcher Kevin's scalp ripped off and worn as a hat.
In "Pressure", Sandy gets into an argument with the other main characters about which is better: Land animals or sea animals. They taunt her until she tries to prove her superiority by taking off her helmet and smashing it. The scene is frightening because her smashed helmet releases an air bubble which quickly floats away, and you can't help but think, "That was her only air!" The worst part is that her friends laugh at her as she begins drowning, until her lungs shrivel up and break off of her airways. Once she realizes she's about to die, she quickly finds a pickle jar which inexplicably has air in it and sticks her head into it.
In the same episode, SpongeBob demonstrates his "sponginess" by budding off several new heads.
"Shanghaied" features Squidward being thrown by the Flying Dutchman into the "Fly of Despair," an apparently endless abyss filled with terrifying imagery and sounds.
Look closely at some of the things in the tunnel as Squidward falls. Some of the things ( including a skull-snake with wings) are downright horrifying and can only be described as " what is that thing?"
It actually does have an end, actually. Marked by spaghetti and meatballs within the rift.
Not to mention the incredibly dark ending with Spongebob, Patrick and Squidward being turned into fruit running away from the hungry Flying Dutchman. Being trapped in his dimension it would only be a matter of time until they were in fact eaten.
According to the Other Wiki, the episode was banned in Australia and Britain for its dark tone and disturbing scenes. The episode it was paired with ("Gary Takes A Bath") was also banned for the popular "subliminal messages" part (its punchline being a picture of a bizarrely-giggling cowgirl).
The episode where Plankton has SpongeBob working for him, and SpongeBob says he'll cook Krabby Patties later. That's not the scary part. The scene that's scary is when Plankton took SpongeBob's brain and made a robot version of SpongeBob.
In that same episode SpongeBob was trying to cook in the Chum Bucket kitchen and opened the oven (or whatever it was) to reveal a mutated burger. The meat part of it actually formed into a hand which it used to pull itself forward in an attempt to get at SpongeBob all the while muttering something incoherently (and creepily).
"Frankendoodle". For some, it's not scary at all, but for others, that babbling, raving voice, its violent intentions, and the way it's drawn are deeply disturbing.
The episode "Graveyard Shift" ended with all the scary things being explained rationally. It turns out the lights had been going on and off because the vampire from Nosferatu had been flipping the light-switch.He's not even animated!
The way Squidward and SpongeBob's eyebrows reacted to the visitor in that episode was creepy.
SpongeBob repeatedly eating his own arms as Squidward tells the tale of the Hashslinging Slasher. It's played for comedy, with no real consequences... but he was still eating his own arms. Full of skin, bones, blood and who knows what else.
As a sea sponge, his arms only contain the last one.
In "Procrastination", SpongeBob dreams that his house catches on fire as a result of SpongeBob putting off doing a report, and it suddenly becomes sentient, using its door for a mouth and port-hole window for an eye, and screams in agony as it burns. There's also the snail clock coming to life and saying in a sinister deep voice "Time's up, SpongeBob!"
The moment that got some was when the power goes out in SpongeBob's house. He lights a candle and hears someone cooing out his name. He turns around and sees his chair has gained a horrific-looking mouth and eyes and is coaxing him to "put his feet up" in a obscenely creepy voice.
The cut scene, in which we see a lovely shot of a REAL LIFE violent car crash. *shudder*
The episode "Jellyfish Hunter", in addition to siccing the nightmarish "Moar Krabs" upon us, contains a genuinely disturbing scene in which SpongeBob is being stalked by a jellyfish, including an infamous "heavy breathing" phone call. It's even worse when No Name, the jellyfish who was stalking SpongeBob, takes him to Mr. Krabs factory where we see the jellyfish SpongeBob had caught for Mr. Krabs are inside tubes, and being forcibly drained of their jelly like they were oranges. The dried out/dead ones are even put into trash cans.
In the "strike" episode, SpongeBob is stuck to a window. When Squidward tries to pull him away, HE TEARS HIS ENTIRE FACE OFF AND YOU CAN SEE HIS INTERNAL ORGANS.
From the episode "Just One Bite": "Does this look unsure to you?!"
SpongeBob: But it's good for you!
Squidward: Good for you? That thing is a heart attack on a bun!
SpongeBob: No, Squidward... I meant, good for your soul...
(angelic background and singing)
Squidward: Oh, puh-leeze... I have no soul!
(hellish background and evil music)
Demonic Voice: Bwahahahahahaaa!
(Squidward's eyes widen, music stops short and he walks away)
The creepily insane look on Squidward's face after he eats the patty he buried underground and runs back to the Krusty Krab.
The deleted scene is also frankly disturbing. See, Squidward first checks if the Krusty Krab has security measures for the Patty Vault. He realizes that it's just a bucket of water placed on top of the door. He laughs about it, opens the door, and the bucket spills over the floor. He steps on the puddle and comments that it's too easy. He then sniffs the liquid and realizes that the 'water' is really gas. A robotic arm then appears and drops a lit match into the gas, resulting in a huge explosion. Squidward then opens the kitchen door, setting off another burglar alarm. The kitchen bursts into flames for a few seconds.
The health inspector episode. SpongeBob and Mr. Krabs believe the health inspector at the Krusty Krab to be a phony who's faking it for free food, so they serve him the a disgusting, moldy Krabby Patty which apparently kills him. The rest of the episode is creepily monochromatic, and about them hiding the battered body from the police.
The episode in which Ms. Puff is blamed for SpongeBob's inept driving and winds up in jail, which to her is a respite from the hell of her normal life. SpongeBob and Patrick, failing to understand, repeatedly try to rescue her, but instead make the guards think she's insane and throw her in an isolation cell. In the cell, she goes insane for real and starts hallucinating that the padded walls are made of sponge, and that each has SpongeBob's laughing face on it. Then she starts hallucinating the beginning of the episode over and over, each time a little different and a little weirder. The episode ends with her giving up on deciding what's real and what's not and resigning herself to insanity. Good thing for Negative Continuity.
It is actually implied that the entire jail episode was just a hallucination Mrs. Puff had while still falling off the cliff, which makes it all the more disturbing. After the solitary confinement scene and Mrs. Puff is shown falling off the cliff again, she has two more hallucinations, and the episode ends with her still falling off the cliff, her fate left ambiguous. Ten times more disturbing in that context. Good thing for Negative Continuity indeed.
The scene in Krab Borg where Mr. Krabs accidentally gets salt in his eyes is rather disturbing. His red eyes and him screaming in pain.
The "young" lady's mother in "Chocolate with nuts". Looking like a mummified corpse with no hair or eyes, and she was literally just a head with a spine! It was supposed to be funny, but it was a little jarring...
The episode where Barnacle Boy becomes evil and forms a league of supervillains after feeling underappreciated. To stop the league of supervillains, Mermaid Man loans the costumes of retired superheroes to SpongeBob, Sandy, Patrick, and Squidward. Each costume gives them the superpowers of the hero that wore it. During the fight with Barnacle Boy and the other villains, everyone's superpower backfires in horrible ways (Squidward, thanks to a mis-aimed water-ball shot by Mermaidman, ending up burning him to cinders, and SpongeBob getting caught running in a circle with his superspeed and DISINTEGRATING are two of the most jarring). In the end it is revealed that everyone is still alive, albeit injured.
The episode with the snail races. The one where SpongeBob overworks Gary, causing the latter's shell and eye stalks to burst in the middle of the race. The one where Gary crashes in a giant fireball against a wall of tires.
The live-action gorilla, emerging from his animated Patrick suit in I Had An Accident.
Though this was more like Ouch Thats Gotta hurt, the scene in the tattletale strangler episode, SpongeBob gets really pointy cleats to jump on the Strangler's shoulders to go to a window, but misses and lands into the strangler's eyes.
Recent SpongeBob episodes are very violent with characters getting skinned, melting flesh, and getting ripped in half. They also make use of the Uncanny Valley trope. Maybe the creators have been "researching" this site.
"Fear of a Krabby Patty." SpongeBob hallucinating? Check. Uncanny, giant talking Krabby Patty that speaks only in horrifying gurgles? Check. SpongeBob terrified? Check. Disturbing allusions to real life psychiatric practices involving convincing patients they are sick just to squeeze more money out of them? Check. CHECK. CHECK!
The "Where's Gary?" episode. Seeing those empty shells in grandma's closet. . .
All those spiders crawling out of that darn crumb.
The episode "Squidbob Tentaclepants" features Squidward and SpongeBob becoming biologically fused due to one of Sandy's inventions. It's not so bad at first, but once everything seems to be resolved, Squidward wanted to be fused again, just so he could be a star... It ends with all the characters becoming trapped in a hideous flesh-colored blob with random moaning heads sticking out of it. It's probably one of the most crowning Nightmare Fuel moments in the show: in fact, it was so bad that some countries removed the scene entirely, thus leaving the episode with No Ending.
The show contained an episode in which the Flying Dutchman's ship breaks down, forcing him to take up residence in SpongeBob's pineapple. The Dutchman tried several mildly scary things in order to disturb SpongeBob, and, towards the climax of the episode, appeared as a huge snake with a huge, grotesque baby's head, which melted, turning into an effigy of SpongeBob, whose eyes elongated into hideous wiggling white worms and squiggled onto the floor while spiders crawled out of his eye sockets and mouth. Also among his forms are a clown's head on the same worm-like creature, and a giant, disturbingly realistic (for this show) insect. It was intended to be a parody of an over-the-top horror movie, but managed to be incredibly horrible.
In all fairness, the point is that the Dutchman has been in SpongeBob's house so long by that point, and pulling so many scary stunts each day, that SpongeBob has become immune to and blase about them.
While the momentary appearance on the creature of a Waldo "Bob" Dobbs head was just downright odd...
The Flying Dutchman also did the same thing to scare Squidward in the end because Squidward didn't believe in ghosts. He also manifested himself as a vision of Squid's mother moaning "Why haven't you called meeeee?" and then melting.
At one part, SpongeBob opens a fridge and a huge monster head suddenly pops out and screams.
In "All That Glitters", SpongeBob breaks his spatula in the beginning when trying to lift a massive glob of patty meat. As SpongeBob is screaming in terror, we get a lovely shot of the half of the spatula's body squirming around in pain under the meat, the Spatula supposedly 'dying'.
Fridge Horror kicks in with other times his spatula was damaged if you believe that the spatula has always been sentient.
In the episode "Once Bitten", Gary gets "Mad Snail Disease" and goes on a biting spree, turning everyone into zombies. Some "survivors" are barricaded in the Krusty Krab, and when SpongeBob arrives (followed by a horde of zombies), the survivors refuse to let him in (although he manages to anyway). But Gary appears out of nowhere and SpongeBob protects him when the survivors decide to kill him "for his own good." However, there was no disease in the first place, and Gary was acting strangely because of a "splinter" stuck in him.
In one scene in the episode "Bummer Vacation", SpongeBob's sitting in Patrick's house after being forced by Mr. Krabs to take a vacation and hiring Patrick as his temporary replacement. When Patrick finds him, SpongeBob looks (and acts) completely insane!
"I'VE BEEN WAITINGFOR YOU, PATRICK."
Then, in the next scene, it's implied that SpongeBob killed Patrick and is wearing his skin. He's not, but just the thought that SpongeBob would prioritize his job over his best friend in the creepiest way imaginable...
In one episode, Patrick has given SpongeBob his prized possession: A House sized collection of gum that he's had for years, which apparently has all sorts of stuff like pizza, clothing and OTHER PEOPLE (they were living in it though). A good moment is when a pair of underpants comes out of the wad and it crawls to SpongeBob until it reaches his face. Then it F@#$ING TALKS TO HIM.
Patrick: Heheh...I thought you were going to say I was abusing my power...
SpongeBob: (Nervous laughter) Well, I—-
Patrick: WHO'S SAYING I'M ABUSING MY POWER!? I'LL PUT THE WHOLE TOWN IN PRISON! QUESTIONING MY AUTHORITY IS TREASON!!!
SpongeBob shrinks and high-tails it while Patrick is screaming
In "New Leaf", when Mr. Krabs tells SpongeBob and Squidward to keep their eyes peeled for any tricks Plankton's playing, SpongeBob takes Mr. Krabs literally and peels his eyes.
"Money Talks". Here's what happens: Mr. Krabs wishes he could talk to money, so the Flying Dutchman grants him that ability. However, the money wants to be spent, and Mr. Krabs, having a Money Fetish, refuses to do so. During the night, the money moan, "Spend us, Speeeeeennnnnnd uuuuuuuuusssss!"
Forgot to mention the fact that Mr. Krabs sold his soul for that to happen. Then it turns out he had already sold his soul to at least 20 other demonic entities, (and Spongebob to weasel out of a paycheck) what the hell is wrong with you Mr. Krabs!?
"The Ick". It's a virus that causes green ooze to grow all over the victim's body. It's contagious on both touch and ingestion. Somehow, Squidward doesn't realize he's scratching a Ick-y spot, and a restaurant full of diners don't notice they're eating it. The only other known symptom is itchiness, but you have to wonder why Krabs called the SWAT team. And why they called the HAZMAT squad.
Ick is a real fish disease. The best way to explain it is that it's the equivalent of a flea to dogs and cats. It reproduces like crazy and feeds on blood and dead skin cells. However, it doesn't manifest itself as green fuzz, rather, it looks like somebody sprinkled salt on the fish.
It becomes more disturbing if you've ever dealt with Ick in aquarium fish. Ick is extremely contagious among fish because it has a fast breeding cycle and the fact that once the parasite encysts, it can stick to just about anything in the tank. If someone doesn't treat Ich, it's 100% fatal among fish.
May be more Nausea Fuel, but there's the GREEN PUS that was SPEWING from SpongeBob!
In "To Love a Patty", SpongeBob destroys a bunch of scallops trying to eat the Krabby Patty he falls in love with. This includes smashing them into pieces and RIPPING ONE IN HALF. This is pretty disturbing on its own, but couple in the fact that they spent an episode raising a baby scallop and it's just doubled.
The episode when Sandy brings a flea back from Texas. There's only one flea at first, but then it multiplies... and multiplies... until there's a huge WAVE of fleas inside the tree dome.
The worst part was seeing the details of the flea. And the screech...sweet mother of God,the screech.
The episode where Plankton brainwashes Mermaidman and Barnacle Boy into hating the Krusty Krab. At one point, Plankton does what he did in his debut appearance and goes INSIDE OF MERMAIDMAN'S HEAD THROUGH HIS EAR, STOPPING BEHIND HIS EYE!
"Eat... or be eaten..."
SpongeBob's crazed look as his sanity slips.
In one episode, SpongeBob and Patrick unearth a submarine apparently buried in SpongeBob's yard. Upon entering, SpongeBob shoves aside a human skeleton to flip the engine switch.
That face from "Whobob Whatpants", arguably more scary than "Moar Krabs" and "Sure Squidward."
"Is there something wrong with me?"
"Spongehenge". Most of that episode is pretty funny, but the ending — where a bearded, crazed SpongeBob heads back to the Krusty Krab only to find it a derelict ruin, evoking the finales of both Planet of the Apes and the original ending of Army Of Darkness — is unsettling: And the final shot of the far-future aliens examining the now-abandoned, eerily-piping huge stone SpongeBobs even more so. It was all somehow reminiscent of the ending of the original The Wicker Man...
In the final seconds, we close in on one of the happily-smiling, piping SpongeBobs, and we hear - over it - SpongeBob's usual merry laughter. But it now sounds completely crazed. Is the implication that a now-maddened-with-loneliness SquarePants has retreated to a recluse's existence inside it?
In "Two Faces of Squidward", an incident causes Squidward to become handsome, however, when SpongeBob tries making him look back to normal in the end, but it makes him more handsome, WHAT IS THAT THING!?
The episode where Krabs grows obsessed with getting a penny that he saw SpongeBob pick up. At one point, he picks up SpongeBob and shakes him down...KNOCKING HIS BRAIN OUT! SpongeBob acts normal even with it off, but to add even more creepiness, the brain GROWS LEGS AND SCURRIES AROUND LIKE A BUG! It even crawls over Squidward, who doesn't even react! And to make things even more sickening, the brain squirts juice (looking like water) at Krabs!
The episode when Squidward tried to get SpongeBob to be normal? Horrifying. Squidward gives SpongeBob a tape on "How To Be Normal". He gets "normal" and looks creepy and says things like "Wonderful weather we're having" in a very disturbing voice... and then Squidward turns "normal" too, and it's FRIGHTENING.
Lampshaded in that the sight of "normal" Squidward scares SpongeBob back to normal.
Earlier in the episode, SpongeBob tries to return to his old self by clenching. He clenches so hard, his eyes pop out, complete with very realistic stalks. His eyes have popped out before, but those gags were usually done in a cartoonish manner.
The episode "Gone" where SpongeBob is the only person in Bikini Bottom and slowly goes insane from loneliness. Finding out that the others were out of town burning SpongeBob in effigy (including his friends) was somehow immensely comforting. Then everyone (including SpongeBob) leaves town to burn Patrick in effigy.
Other aspects of "Gone" were unnerving. The title card itself evokes a sense of how empty the town is during the episode just seeing the word over a barren landscape. Plus, the idea that everyone organizes a special occasion to burn you in effigy and that you even partake in it when it's someone else being burned in effigy isn't too pleasant either.
The episode where SpongeBob gets a splinter in his thumb. All of it.
There's a rather gruesome scene in "Plankton's Regular", where SpongeBob is lying in front of the Chum Bucket's door, and the regular customer opens the door over him, scraping off his face in the process. It doesn't get really disturbing until he sits up, and you can see all the (rather detailed) muscles of his face exposed.
"Squid's Visit" has a somewhat creepy premise, with SpongeBob making his entire house look EXACTLY like Squidward's down to every minor detail. But the real creepy parts are when SpongeBob is heavily breathing with a crazed look while staring at Squidward, and at the end when Squid's house burns down-he then gets a VERY weird looking expression, and then has a fantasy of him having tea with his vacuum and he then says "Yes, I'd love another spot of tea Mr. Vacuum Cleaner!" and "care for some casserole?" in an eerie tone underscored by unsettling background music, and then he starts laughing insanely with his eye-twitching while the screen zooms in on his face.
One of the new episodes where Gary breaks his shell and needs a new one. SpongeBob goes to this discount snail shell dealer named "ANGRY JACK" and breaks all his shells. Afterward Jack asks SpongeBob to "pay him back" in terms of body parts. He takes his one of his arms, a leg, and his heart (which looks realistic). Why Angry Jack wants those aren't something to be thought about.
The cave dwellers in the episodes Chum Caverns and another one are downright horrifying. You would think the scene where Plankton gains control over them, despite them being 50x his size, would be funny. Plankton whips them into submission, and they begin crying in fear, and obviously pain from the whip. So, you would think it's just the evil empire of the Chum Bucket that harnesses their power, but later on, The Krusty Krab also uses them. But not to fear, they're treated better. The cave dweller monsters get to use the whips.
Infamous enough to the point where it gets compared to THAT "nail scene".
"Someone's In The Kitchen With Sandy" features Plankton stealing Sandy's fur and puppeteering it like some sort of grotesque flesh-robot. The act of obtaining the fur isn't so bad, as Sandy apparently wears it like a suit so she can just take it on and off, but the flesh-puppet that it becomes, with its Zombie Gait and nothing in its mouth and eye sockets...
The premise of "The Inside Job" is that Plankton has a new plan to get the secret recipe for Krabby Patties by going inside of Mr. Krabs, which ends up being SpongeBob due to a misfire, and taking over his senses. First, he takes over his sight, causing Spongebob's eyes to go COMPLETELY BLACK, and for him to panic at being blind and make a patty out of soap, sponges, and a scouring pad. That doesn't work. Plankton takes over his hearing next, which doesn't lead to anything Nightmare Fuel-ish other than the idea of suddenly losing your hearing because somebody's stolen it. Plankton then decides to go into SpongeBob's brain, where there is a complete version of SpongeBob's house made out of brain, including Gary! The episode then turns into utterly terrifying Body Horror. Plankton plugs his sense-stealing device into SpongeBob's heart, and becomes a SpongeBob-looking thing, completely with a scary transformation sequence. He later becomes Patrick, which is played for laughs but doesn't excuse the second transformation sequence.
Greasy SpongeBob. In the episode "Greasy Buffoons", The Krusty Krab has to clean up a lot of grease before they can reopen. So, they use SpongeBob. He became this saggy giant SpongeBob with all the holes swelled up and full of grease. Ughhh...
In "A Pal For Gary", Gary is paired with a creature of similar size that opens its mouth and reveals tons of horrible-looking teeth. After eating a fridge worth of food, it grows into a massive, disgusting, all too detailed Eldritch Abomination with multiple sarlacc-like tongues and tries to eat Gary and SpongeBob.
Spongebob 's behaviortowards Gary in that episode was nightmarish; beyond sheer stupidity and ignorance. The entire episode Fluffy is flat out trying to murder Gary and everytime Gary goes to Spongebob to help him, the yellow idiot thinks Gary is being mean to Fluffy and not attempting to give the new pet a chance. At one point, Fluffy chews apart one of Gary's chew toys savagely with Spongebob in the same damn vicinity and just casually eats food and goes on to blame Gary.
The old snail from "Gary in Love".
Squidward's nightmare sequence in "Squidward In Clarinet Land".
The disembodied Eagle head threatening him and laughing oh-so-creepily.
Mr. Krabs opening the locker and there being a skeleton inside. He makes a comment about SpongeBob asks Mr Krabs "Who is that?" and he responds "That appears to be Corporal Sterling. Forgot about that prank..." Possibly meaning he locked someone in the locker and they DIED!!! Mr. Krabs KILLED SOMEONE!
The file cabinets in the safe getting bigger and more mazelike was scary, it was not helped by SpongeBob laughing and running around in there.
To some extent, parts of "Earworm". One scene when SpongeBob ran back home like crazy while singing to the tune of "Musical Doodle, "The song that you ran from is back again. You wonder will the madness will ever end".
That whole scene. The Room Full of Crazy and SpongeBob's weird humming/babbling and whatever he was doing with his hands, "running" home on all fours looking utterly deranged, crawling up and down around the outside of his house and in through a window while creepy music plays...that whole sequence was just unsettling. The very premise of the episode: if a song gets stuck in your head, a parasite will take up residence in there and drive you completely insane.
"Round n' round, the record spins all day, listen again, it takes you FAR away..." feels like the song is telling you that you'll go mentally insane (which SpongeBob does) and wind up in a mental asylum if you listen to it repeatedly.
One scene that really crossed the line was when the earworm CRAWLED INTO SQUIDWARD'S HEAD THROUGH HIS EYE in his sleep. Then at the very end, Squidward screams.
The episode in which Bikini Bottom is invaded by giant sea whelks who eat everything in sight. As if the premise wasn't scary enough, there's a scene near the end where SpongeBob and Patrick lend their corneas to Sandy.
The episode with the time capsule. It revolves around SpongeBob, Patrick, and Squidward getting stuck in a time capsule and buried alive.
"That Sinking Feeling" from Season 7, where Spongbob and Patrick get everyone's houses buried underground. The premise isn't scary, but we get a scene where we see from first person view Squidward ANGRILY walking down a dark, claustrophobic tunnel up to Spongebob and Patrick, like something out of Amnesia or Slender. Said scene also switches between the first person view of Squidward & the fearful reactions of Spongebob & Patrick.
The snow-monster thing from "Frozen Face-Off". It looks like a cross between Squidward and a Yeti, which is a lot worse than it sounds, especially because it's not animated in 2D animation, but in something that looks like Claymation
In "House Sittin' for Sandy", Spongebob suffocates once again by being inside Sandy's treedome sans helmet, but the newly redesigned way it's shown is beyond anything they've shown before.
In "Walking the Plankton", Plankton gets chopped in half by the boat's propeller blade.
In one episode Plankton decides to grow another eye resulting in many body horror scenes. Including one where eyes grow all over his body including inside his mouth. "I CAN SEE EVERYTHING!!!"
The second half of "InSPONGEiac", dear gosh. SpongeBob loses sleep and halfway through the episode, Patrick gives him coffee to help him which makes him run uncontrollably. The scary part is when he starts hallucinating.
In "Squiditis", when Squidward fakes being sick and lists his symptoms, mentioning "itchy eyes," he scratches his eye! Later, SpongeBob does it too!
Squidward being fried alive and almost eaten in "Restraining SpongeBob".
"Planet of the Jellyfish" where alien jellyfish invade Bikini Bottom. They replicate everyone, except for SpongeBob and Sandy, speaking in a robot-like tone and having soulless black eyes. The alien leader is keeping the real Bikini Bottom citizens in pods hanging from the ceiling in the freezer. It becomes slightly Nightmare Retardant when you find out the aliens Weaksauce Weakness is...mayonnaise.
"Demolition Doofus". Mrs. Puff gets deflated (creepy in itself) and tries to kill SpongeBob. Not beat or injure him. Murder him.
If that wasn't bad enough, her dialogue only makes it more disturbing:
"Face Freeze". The entire episode consists of the main characters (aside from Sandy), making the most grotesque faces in the entire series. Especially in the end...Mr. Krabs and Squidward...
Santa, of all people, in the Christmas special. At first, he appears as a huge, extremely uncanny face watching the residents of Bikini Bottom. Then, when he actually comes down to the town, he looks vaguely like a pig-goblin hybrid.
In "License to Milkshake", Captain Frostymug is graphically sucked into a milkshake maker.
The old snail from "Gary in Love" makes another cameo in "Plankton's Pet".
Also, the scene where Mr. Krabs attacked the baby which was Plankton in disguise. The customers were so horrified by this that they started beating Mr. Krabs up.
"Squid Baby" may have the most horrifying And I Must Scream moment outside of the movie to date. Squidward gets a brain injury so bad, he has the mentality of an infant for the majority of the episode. The doctor said that he would stay a baby forever if his head kept getting hit long enough. Guess what happens to Squidward for most of the episode regardless of the fact he gets better at the end.