Villainous Breakdown/Theater

"Out, Damned Spot!! Out, I say!"
 * Shakespeare - Claudius in Hamlet goes from a politically savvy, brilliant villain, to ending up in a religious crisis, to coming up with the worst poisoning scheme in literary history.
 * Macbeth in Act 5
 * His wife gets it even worse:

"You have murdered me! You have murdered me! Murdered! Murdered! Murdered! Murdered!"
 * Archetypal Machiavellian Magnificent Bastard Richard III goes through a Villainous Breakdown just before the play's final battle, hallucinating that the ghosts of everyone whose deaths he's caused are visiting him and telling him to despair, and ultimately realizing that after everything he's done, the entire world (including himself) hates him utterly.
 * When King Richard lashes out at a messenger bringing news of his enemy Buckingham... only the message turns out to be that Buckingham's army has been defeated.
 * The Wizard has a very quiet dignified one of these at the end of Wicked where he learns that the Wicked Witch whom he believes was successfully assassinated on his orders was actually his daughter. He sinks to the ground completely ignoring both his ally and the returned and angry Glinda for a long while.
 * Sweeney Todd: The Demon Barber of Fleet Street has a pretty epic one right in the middle of the play after the title character's first attempt at revenge on Judge Turpin goes awry. The result is the awesome "Epiphany" number that marks his transition from Anti-Hero to Villain Protagonist.
 * And it happens again at the end of the show when he finds out
 * In One Flew Over the Cuckoo's Nest, McMurphy spends most of the play trying to make this happen to Nurse Ratched.
 * Judas in Jesus Christ Superstar. Same as in The Bible, he is Driven to Suicide but the rage in his My God, What Have I Done?? number lands it solidly here.


 * Salieri from Mozart L'Opera Rock, notably in the showstopping "Le bien qui fait mal" number, which combines him going insane with jealousy with some intriguingly sadomasochistic lyrics ("it feels so good to sufffer", "real delights require torture", "I love having [this insanity] inside my skin", etc.) He's a special sort of guy.
 * Though he's not really a villain per se, Inspector Javert gets a pretty spectacular breakdown in Les Misérables because he doesn't understand why
 * In the Broadway version of The Lion King, Scar has this in The Madness of King Scar, where he imagines that he sees the ghost of everywhere.