Mind Rape/Web Original

Psychic Assaults

What's worse than being mind raped? Being mind raped by a Giant Spider. One who is quite clearly enjoying herself. N'Ktane does this in Tasakeru.
- And so does her "son", Stalker, later in the same series. And he doesn't just stop at mind rape...
In the second I'm a Marvel... And I'm a DC story "Happy Hour", The Joker's plan essentially involves using a mind-controlling cyborg to rewrite the memories of all the superheroes to make them Darker and Edgier by putting them under the delusion that everyone they ever loved had been brutally murdered right in front of their eyes. He also uses that android to psychically torment Green Goblin by forcing him to learn the entire Portuguese language... all at once.
On this page of the scp wiki, Dr. Alto Clef explains that he is Satan, has just gotten God put in a coma, and that Heaven is empty and waiting for his legions to invade. He then reveals that this isn't true. Then that he is a notorious liar, and he could be lying on any or all of these points. Dr. Clef then falls against the table, managing to hit his head nine times.
Given that Mortasheen is a horror take on the standard Mons setting, you could probably guess that this trope pops up a lot. It is most notable in the Devilbirds, most of the Vampires (Who have some level of hypnosis to lure their prey to them) and about half the creatures in the Unknown category.
The Slender Man Mythos sometimes does this to people, perhaps when he feels they're resisting him too much, perhaps just as a side effect of his presence.
Happens in Arcana Magi to Alysia Morales and Reya Everheart. The process is called Therapy and for Alysia, she found it humiliating before her mind broke and she was no more, but for Reya, she is completely afraid of it and even warns Alysia not to mess up or else.
What happened to Cavalier and Skybolt in the Whateley Universe. And it turns out to be worse than we suspected.
Red vs. Blue Revelation has Tex state that part of Alpha's torture was being placed in scenarios where he was forced to try and fail to save his loved ones, and being forced to watch them die. Repeatedly.
- Further, it was tortured this way by facets of its own personality (Gamma and Omega) on the order of the human it was based on. Which would add that it would believe itself capable of inflicting this sort of agony on others.

"Mundane" Torture

This is basically how the story of Broken Saints treats Shandala. She suffers one horrible thing after another in her life, eventually resulting in becoming an empathic weapon designed to do this to millions of people across the world, employed by the Big Bad in his plan to all but restart human civilization.
This happens to the people in Shell after they look at the Eldritch Abomination.