- The spectre. We don't even know if it really is the soul of the dead king; it could be a demon planning to damn Hamlet. If so, it succeeds.
- Ophelia's madness can come across as quite disturbing - especially since she even loses her self-preservation instincts.
- In Julius Caesar, the scene where an innocent poet is literally torn to pieces just because he shared a name with one of Caesar's assassins, Cinna. This is something that could happen to anyone.
- The infamous scene in King Lear in which Gloucester is blinded.
- Iago from Othello. The idea that someone has the ability to persuade otherwise decent people to commit murder is highly disturbing, and the fact that nobody has been able to completely put a finger on his motives doesn't help.
- Titus Andronicus is full of it, with all the killings, dismemberings etc. Moments that stand out include:
- The sheer extent of Tamora's planned vengeance. She won't rest until the entire Andronicus family is dead.
- Demetrius and Chiron raping and horribly mutilating Lavinia and then taunting her about it afterwards in a horrifying manner.
- Aaron casually stabbing the nurse out of nowhere to eliminate witnesses to his baby's origin.
- Aaron's speech about all the many wicked deeds he has committed, including digging up dead bodies and placing them on their friends' doorsteps.
- Titus baking Demetrius and Chiron into a pie and serving it to their mother. (Granted, they all had it coming, but still...)
- The ending of The Two Gentlemen of Verona may be this for Silvia. Her boyfriend Valentine briefly offered her to her would-be-rapist Proteus, who is his best friend, and thinks nothing of talking about how they will all live together (if his final line about "one feast, one house..." is to be taken literally).
Nightmare Fuel / William Shakespeare