Think the macroviruses were bad in Star Trek: Voyager? Now imagine the bugs an infected Paul Bunyan would produce. Imagine how big a bug would have to be to stab an adult human through the heart.
A Mary Sue could completely Mind Rape you, and there's nothing you could do about it.
In Tom Paris Is NOT a Wimp, a character replacement is given a glass of hydrochloric acid. The author describes the results.
Agent X is Ax-Crazy even by PPC standards, and even her friends are afraid of her. Fortunately, the author of Sue Be Nimble, Sue Be Fast does not traumatize the reader with a description of what she [X] did to the Mary Sue.
Any Fan Fic tackled by the Disturbing Acts of Violence Department.
The Word Worlds tend to create literal interpretations of poorly-phrased or mistyped sentences, causing the characters to actually do the things described even if they clearly weren't meant to. Or there are cases where they were meant to do the physically implausible things, thanks to a Critical Research Failure on the author's part. The agents have to watch this. Notable examples include a pornographic fic which kept mixing up or dropping tags, so both characters performed every action described upon the other at the same time. Or the one in which one character managed, in Agent Deuce's words, to "stick his thing into the other guy's thi-"or turning the male lead into a giant walking sandwich is Nightmare Fuel or a Crowning Moment of Funny.
Some agents have the Bloodwrath, and can be set off with trivial ease.
The Mind Extractor. It rips you from your body and plants you in another.
Agent Verra seems to be a Yandere, and has threatened to eat Alec on at least one occasion.
Agent Madison O'Grady. Okay, so Billy Bannister has fiery breath too, but he isn't in a line of work that corrodes one's sanity.
What, no mention of For Your Eyes Only? The notes for the mission (VERY not-work-safe) described it as "offensive at best", which doesn't really cover the creepiness at all.
It's enough to make anyone curl up into a little ball and rock backwards and forwards crying, even if they're not a fan of Naruto. The... thing that replaced Naruto is an insult to ninjas worldwide.
And what happened to Sakura-bunny is pure Nightmare Fuel... especially because right afterwards, the only thing that happens to her killer is that he's lightly rebuked for killing the only totally submissive pet-thing they had. Repeat: He was lightly rebuked for murdering another sentient being. Not because he killed a sentient being, not because she hadn't done anything wrong, just because they didn't have another pet that'd fuck anyone. The mind boggles.
Fridge Horror applies to the experience of Gorillaz's 2D in "Gorillaz in the MST". He agreed to do the MS Ting to get away from the whale which had canonically been staring at him for months (It Makes Sense in Context) and wasn't told what the sporked fic was about. He realised too late that it involved him being raped. By Murdoc, who was also in the theatre as a riffer. And, in accordance with traditional MST rules, he wasn't allowed to leave. Murdoc just laughed it off, but poor 2D was pretty uncomfortable. Hemlock's abrupt Nosebleed upon the mention of 2D in drag probably didn't help.
Agents Laura and Danny take down a Stu in a Left 4 Dead fic, shoot him in the knee and leave him there, with a gun just out of reach and a horde of Infected approaching... sure, the guy deserved it, but ugh...
Another Left 4 Dead fic involved Zoey screwing a talking Hunter called Zion. *shudders*
A Stargate Atlantis mission had the author continually misspelling 'lab' as 'lad', creating a ten year old boy called the Science Lad. A late line in the fic had one of the doctors 'entering into the lad with some of his medical assistances'. Thank God Agent Thomas had a Sim Gen. Similarly, one has to feel for the Bride of Khazad-Dum; poor woman got stretched out over a chasm and had the Fellowship walk over her.
A malfunctioning Crash Dummy led to Agent Cadmar becoming forcibly genderbent and having horrific scars appear all over his/her back. These scars not only gave him/her horrible flashbacks, he/she was unable to so much as take a shower for fear of remembering how he/she got them in-fic.
This also lead to a Crowning Moment of Heartwarming-initially, the Flowers decided to leave him/her as a girl and the scars as punishment for the mismanagement that lead to the clusterfuck that was the mission. However, when Miah brought up the sheer trauma of the scars, the Sunflower Official decided to remove them without hesitation. Keep in mind that the Flowers are regularly portrayed as the most stubborn and irritable beings in the universe, so partially reversing a decision is a monumental action for them.
Agent Ally nonchalantly coming up with new and interesting ways to kill a regenerating mini-Sue, especially as she does so without turning a hair at the fact that she's repeatedly killing a sentient being.