WARNING: Spoilers Off applies to this page. There will be unmarked spoilers below. Proceed at your own risk.
GARDO, the robot from Home Insecurity, with its complete lack of any of HELPER's emotion, extreme strength and it's downright brutal methods of killing, the results of which we witnessed when Brock returns at the end. Hell Brock may have only been saved by the fact that he ran the damn thing over.
Tiny Attorney. The man is a midget GROWING OUT OF THE STOMACH OF AN INBRED MAN that sounds as if he suffocates whenever Tiny comes out.
In the season two opening episode, Powerless In the Face of Death, Orpheus attempts to bring back Dean and Hank after their deaths in the first season finale. But he can't find their souls. What turns from a nonchalant Funny Moment as he casually goes on about the whole thing while his daughter Triana is crying and horrified by the implications, jumps into this trope when he opens the door due to knocks, only to find clones of the boys without their skin. Even worse? As the screen fades to black for commercial break, we get realistic skulls transposed over their heads faintly.
The feral gorilla in the E-DEN dome in The Buddy System is pretty horrific especially when a traumatized and brutally injured Quiz Boy mentions how he saw it disembowel one of a group of children he was looking after in the dome. Even more disturbing is Dr. Venture's response to the child's death in that he decides to tell the other kids that the gorilla was just a man in a costume as part of a show and never tell anyone of the child's death, including the child's parents. The parents later appeared and Dr. Venture gave them a poorly grown misshapen clone of their son to take home.
But going back to the E-DEN dome, it has a very creepy atmosphere. The thing Dr. Venture and the tour happen upon that finally motivates them to leave is a Human Skeleton that has it's skull and pelvis switched around, and appears to have been set up deliberately. It's unclear as to what put it there, whether it was the gorilla (Which by itself points to some highly disturbing implications about the creature) or if there's something else, something much more sinister living in that dome that we never see,
The hologram of the Soveriegn. It's like some weird live action/CG/animation hybrid that doesn't quite move like it should, and it's unsettling as hell, even if what he's saying is hilarious.
The Reveal in What Color is Your Cleansuit, that the college interns are mutating into monsters, except for the green suited ones. When Sargent Hatred hears they only eat "Student Green" he thinks its a vegetarian diet, but he soon witnesses first hand that "student green" refers to the green suited people. Bonus points for being a Shout-Out to Soylent Green
Sargent Hatred: Oh my god...it's people!! student green is made out of people!!! (cuts to him being carried off by four other mutants apparently oblivious to what's happening to him) WE GOTTA STOP THEM SOMEHOW!!! WE GOTTA TELL DOC!!! IT'S PEOPLE!!! STUDENT GREEN IS MADE OUT OF PEOPLE!!!!!!!
Ultimately, the episode ends with the Monarch and Dr. Girlfriend reversing the mutations and all the students turn back to normal. Of course, that doesn't do anything for all the green-suited ones who were murdered and eaten. They're still dead, and all the other students have to live with the fact that they're cannibals for the rest of their lives.
This part depends on your point of view as to whether or not it's nightmare fuel or Black Comedy, but one of the green suited interns implies that the mutants haven't gone insane at all. They are just a bunch of social outcasts who watch too much SyFy. Meaning that they kinda brought all of this on themselves. On the other hand, it didn't take much at all for the students to turn in remorseless killers, so they always had the capability to act like monsters. The mutations were just their excuse.
The Investors took a huge step in this direction in "O.S.I. Love You." We already knew that nothing can touch them, they can float through floors and walls, and carry people with them. That means they can take you and kill you the moment everyone's back is turned. Oh, and now they can shapeshift and flawlessly imitate anyone. They keep the Guild running smoothly and do a damn good job ensuring that no one snitches.
To help you understand how terrifying they are, there is an example of how freaked out Monstroso got when he saw a glimpse of them when he was being interrogated by Brock Fucking Sampson. Note: Monstroso has gotten his ass kicked by Brock at least twice and the second time has taunted him by having sex with the love of his life in front of him, surrounded by OSI badasses and knowing that Brock's going to take it out of him, but he still does it just to piss him off. Yet at the mere glimpse of one of the investors he panics, runs all around the room, and knocks Brock out by accident: by flipping the table he was being interrogated at on top of him and running over him a few times just trying to get away from the investors. And that's not even going into the pure paranoia fuel these guys ramp up by just using their powers.
Myra has Dean tied up. So she can shove him up her vagina and give "birth" to him which is already scary in-and-of itself, but made even creepier by the fact that earlier she told him to get undressed and "show mom that handsome new body."
Despite being bat-shit insane, Myra apparently turned an entire insane asylum and a few guards into her obedient cult. Through sheer willpower. When they snap out of it, it's treated as though they were breaking out of hypnosis or brainwashing. It was just Myra. Hell, she even managed to convince Dean to follow her. True, he wanted to bail the moment he was actually with her, but she still got "done-with-this-shit" Dean under her thrall.
The flashback where Myra is arrested by the OSI is pretty unsettling, as she beats up the agents sent to arrest her and frantically charges at Dr. Venture while giving off an ungodly screech. Luckily she's knocked out before she gets to him.
Hell, Myra in general. Her insanity isn't played for laughs at all and she really comes across as dangerously psychotic.
From The Stinger of Bot Seeks Bot: if you're on the Guild's master Council of Thirteen, have ever been in the Chamber Sub Rosa, or anywhere close to the innermost workings of Guild society, guess what? The Revenge Society is WATCHING YOU!
The flashback of M.U.T.H.E.R.'s attack on Jonas' state-of-the-art fallout shelter. As the members of Team Venture are giving orphans a friendly guided tour of the shelter, M.U.T.H.E.R. unleashes some kind of psychotropic gas onto the track, sending them all into blind frenzies. The Action Man sees thousands of bugs crawling out of his clothes, Col. Gentleman sees himselfgetting a blowjob from a strange creaturenote Who either is or resembles the Rodent Villain seen in the Guild video in "Fallen Arches" and begins desperately scratching at the walls to escape until his fingers bleed; which is all to say nothing of the dozens of hallucinating, screaming children running around everywhere... oh God, the children's screams...
This is made even worse when you remember they ditched those kids in said tunnels for 40 years.
Whatever it was, the alien that killed the Grand Galactic Inquisitor really looked like was this in-universe for all present. The sight of it horrified even Brock, and everyone nearly crapped their pants; except for Ned, who DID crap his pants.
The deformed Dean clone is clearly insane. However, it just gets worse when he treats everything like Dean does. Listen to how he says, "there's no more left", as in, there's not more clones for him to kill and skin to get the materials for his "super secret project" read as a Genuine Human Hide. It complains about there not being enough left as if he's referring to someone eating all of the cake. He sounds so innocent for a madman.
The ghost of Major Tom is just creepy with the scream and the glowing green flames and some of the skeleton exposed.
Don Hell's death. He is dissolved by something he drank.
The Moppets are pretty nightmarish, especially in their willingness to mutilate their victims in ways that even disgust Brock Samson and the Monarch!
The SAW reference with two villains locked in a basement doesn't help either, especially considering one of them ate the ass meat of the other dead prisoners. Then that same one goes insane, brains the other with a pipe, and eats his ass too with the inference that he killed the rest. The Stinger to all this? #21 didn't actually kill any villains past the first, he locked them all up down here and made sure they were fed and this one villain killed the rest out of a psychopathic breakdown. And then it's implied Red Death devours him and the corpses anyway.
Dr. Mrs. The Monarch finding a Blue Morpho dart in her. It's Played for Laughs because we know the circumstances behind it, but what about from her perspective?: There's a masked killer on the loose, who's targeting members of your organization, whose well-being you are responsible for. After a hectic day at the office, you come home to relax with your husband in a bit of sexy roleplay, and the next thing you remember is waking up hours later with the killer's calling card sticking out of your buttocks and the love of your life unconscious on the floor. The freak was in your house at your most vulnerable! He's obviously taunting you by showing he knows where you live and can come after you or your husband at any time.
Red Death describing the "Movie Night" incident on Gargantua-1 during "The Rorqual Affair". Unlike Manstrong, who treated it like a campfire ghost story, he was there to see the horror of the whole thing.
Red Death: You ever see a man die in space? You can tell the ones who held their breath. Their lungs rupture from all that gas expanding. Blood from their mouth like a torn pillow stuffed with red BB's. Stab Girl, she was a little thing. Carried switchblades. She knew to exhale. Watched her for a full minute. Puffed up like she had a peanut allergy. Floating by me with her mouth open, screaming, making no sound. Spit on her tongue boiling.
As one YouTuber said, it's hard to tell if he's suffering from PTSD or if this is one of his happier, more fascinating memories. It's probably the former, but the fact that you can't tell for sure makes it chilling especially if he's convinced himself it's a happy memory.
The severed, yet still-living head of Jonas Sr. letting out a ghostly NO and one hell of a game face◊ as he ensnares Venturion/Vendata/The Blue Morpho (and accidentally, Rusty, standing nearby) in a final desperate attempt to take over the body of the former; cementing not only his status as a world-class asshole, but a monster.
The blank eyes and frozen scream of Jonas Sr.'s head as it hangs limply◊ over the side of the P.R.O.b.L.E.M. machine, seemingly dead for good this time...
Dr. Mrs. The Monarch proving Red Death isn't the only one capable of delivering pants soiling speeches, when she describes The Tub to S-464.
Dr. Mrs. The Monarch: It's called The Tub. It's filled with milk, you lay in it, if you're hungry we pour honey on your face.
Dr. Mrs. The Monarch: At first. Til the milk spoils. Soon the tub fills with your excrement, then the flies and their maggots. At first it itches a bit. Then it starts to burn. Your skin peels away with every scratch you can't stop yourself from making. The blood mixes with the foul milk and excrement, seeping into your open wounds. The smell of your own death causes you to vomit into your already toxic coffin. Then the rats...
After Blind Rage insulted Dr. Mrs. The Monarch and Red Death, Red Death decided to get revenge and did a classic train tracks before a train arrived. The quote also is scary:
Red Death: Oh, you're up. Goody. We can start your history lesson. Long before there were loudmouth buff guys in spandex, there was the gentleman villain. His favourite sinister act was this: tying someone to a train track. It's simple, inexpensive, personal and deadly, but it gives you a little hope - maybe you'll escape. [Blind Rage's muffled screams interrupt]Lesson's NOT over, sonny! *sighs* Now, the gentleman villain had these old school time-bombs, three sticks of dynamite wired to an alarm clock. And what was so poetic about that is that they ticked. You could hear them - tick tick tick. Nowadays they're just digital - no sound, no peril. [the sound of an approaching train is heard, getting closer] Oh, ohoho, do you hear that? There's the ticking. The train is coming! Is it on this track? Tick tick tick. Maybe it's on the other track! Tick tick tick! *cackles maniacally* Not bad for an old man, huh? I'm gonna get going, let you try to escape. And if you do, tell the Peril Partnership that the Guild isn't scared of punks. If you don't, eh, sorry.
What hammers home just what Red Death decided to go old school, aside from dismissing him as an old man, is that Blind Rage had already bragged about how powerful his non-visual senses were. Blind Rage wasn't panicking just because he was in danger. He was panicking because he knew exactly how far away the train was, how fast it was going, and which track it'd be on, before Red Death even started taunting him over the helplessness of it. Red Death made sure Blind Rage's own brain described his death To the Pain.