- The entirety of Bartók's Bluebeard's Castle is filled to the brim with pure nightmare fuel, considering its source material. The opera's set in a dark and creepy castle with seven locked doors, and there's already a rather cold feel in the relationship between Bluebeard and his new wife Judith. Let's not forget about the dead ex-wives. The score itself is incredibly terrifying.
- Richard Strauss' Salome is incredibly messed up, in addition to being scary. There's Princess Salome, who's willing to strip for her stepfather before demanding the head of Jochanaan. If that weren't enough, at the end, Salome actually kisses Jochanaan's severed head and declares her love for it in front of everyone. It horrifies Herod enough to order her to be executed.
- Verdi's Macbeth, much like Shakespeare's original play, is filled with this. There's the part when Lady Macbeth kills King Duncano when her husband can't bring himself to complete it, and the scene when Macbeth sees Banco's ghost at the dinner with the other nobles. Of course, there's also the Witches, who are now an entire chorus and not just three witches.
- Yet another Richard Strauss opera, Elektra, also contains plenty of nightmare fuel. After King Agamemnon of Mycenae is murdered by Klytämnestra and her consort Aegisth, Agamemnon's daughter Elektra becomes obsessed with avenging her father's death to the point of insanity. Elektra repeatedly fantasizes about avenging her father's death, and even dreams of dancing in celebration. However, things reach the breaking point when her brother Orest returns to Mycenae, and it results in a bloodbath, in which Klytämnestra, Aegisth, and all their followers are massacred. But what truly makes this creepy is at the end of the massacre, Elektra is so elated with avenging Agamemnon's death that she dances herself to death. And to top it all off, when her sister Chrysothemis to get Orest, there's no answer at all. Real chilling.
- Mad scenes in operas are filled with this:
- Lucia's mad scene from Donizetti's Lucia di Lammermoor is both Nightmare Fuel and Tear Jerker. Already, Lucia is a fragile character, but her mental state rapidly deteriorates when her brother Enrico threatens to haunt her if she doesn't marry his ally Arturo. Lucia's offstage murder of Arturo sets the tone for the incoming aria "Il dolce suono" before she comes in with a bloody wedding dress and completely unaware of her crime, instead singing about a supposed happy life with her lover Edgardo. The way she acts as if he's there and singing to him is both chilling and heartbreaking. Even worse, Lucia dies from her madness, which really emphasizes how frail of a woman she really was.
- Yet another Donizetti opera, Anna Bolena, has a mad scene. It focuses on the final days of Anna Bolena (Anne Boleyn) as the wife of King Enrico VIII (Henry VIII) of England. Not only is she in the Tower of London awaiting execution, but when she goes mad, she imagines that she's marrying Enrico, before imagining Riccardo Percy and asks him to take her back to her childhood home. Even worse, right before her execution, Anna snaps out of her madness, and despite being condemned to death by her husband because he took on a different woman, she doesn't wish any ill upon them.
- Hamlet by Ambroise Thomas, again based on Shakespeare's famous play, has Ophélie's mad scene. To start off, Ophélie has gone mad from Hamlet's rejection of her, and has wandered into the countryside, encountering some peasants while dressed in a nightgown and having flowers and vines in her hair. She tells the peasants not to believe the news of Hamlet's rejection of her, hands flowers to the young girls in an upbeat melody, before shifting to a somber melody and singing about water sprites that drown lovers. And at the very end, Ophélie drowns in the river, just like Shakespeare's play. It even follows Gertrude's description of Ophelia's death in Shakespeare's play!
- Bizet's Carmen has the scene when Carmen and her friends Frasquita and Mercédès read fortunes from tarot cards. While Frasquita and Mercédès' cards promise love and wealth, Carmen's cards repeatedly show the death of both herself and her current lover Don José. Then there's the Fate motif constantly being played during certain scenes, especially when Carmen throws the flower at Don José in Act I, almost telling us that Carmen's fate has been sealed the minute she chose Don José.
- Puccini's Tosca has quite a bit of this. Act I has Scarpia's plans to kill Mario Cavaradossi and rape his lover Floria Tosca, but it's nothing compared to Act II. The second act features Cavaradossi's offstage torture, in which he's described as having a strap on his head with hooks digging into his skin that make him bleed whenever he refuses to tell the truth. Worse, we don't even see it; all we hear is Cavaradossi crying out in pain offstage and Tosca's own horrified and despairing reactions as she begs Scarpia for mercy. Then, there's Scarpia's namesake ultimatum in which he attempts to blackmail Tosca into sleeping with him in exchange for her lover's life.
- Already the story of Der Freischütz by Carl Maria von Weber is scary enough, what with a hunter making a Deal with the Devil for magic bullets, but there's the scene in the Wolf's Glen. The last bullet's path is not controlled by Max, but by the Devil himself.
- Arnold Schoenberg's opera Erwartung is the operatic equivalent of a psychological horror movie. The only role is an unnamed woman, sung by a soprano, who is searching for her lover in the woods at night. Upon coming across a tree trunk that she thinks is her lover, she unleashes a tirade of fears and emotions. But when she comes across the actual body of her lover, she tries reviving him and even accusing him of being unfaithful to her. It's honestly terrifying.
- The end of Mozart's Don Giovanni, when Donna Anna's father, the Commendatore, rises from beyond the grave in statue form and drags Don Giovanni to Hell as punishment for his sins.
Nightmare Fuel / Opera
Believe it or not, even opera itself is filled with plenty of moments to give you nightmares for a good while or so.