Probably the most famous of these is Donizetti's 1835 Lucia di Lammermoor in which, in rapid succession, the heroine weds a man she doesn't love, has a humdinger of an argument with the man she does love (and to whom she considers herself already married), and then stabs to death her undesired groom (who seems a nice enough fellow, but definitely in the wrong place at the wrong time). Let's look at Lucia's first "wedding" before moving on to the fury and gore. Lucia and Edgardo have a clandestine meeting on the grounds of her estate and they marry themselves via their own divine oath, sworn to the open heavens above them: "Dio ci Ascolta, Dio ci vede; tempio ed ara e un core amante" - "God hears us, God sees us; a loving heart is both church and altar." They exchange rings. Her brother Enrico, though, is prepared to do anything to force Lucia to marry another man, Arturo, to boost the sagging family finances; and he produces a forged letter claiming Edgardo is unfaithful. Shocked by the news, Lucia still feels in her heart that Edgardo is true to her. She consults with her sympathetic old tutor, Raimondo, who sadly informs her "I nuziali voti che il ministro di Dio non benedice, nè il ciel, nè il mondo riconosce" - "Nuptial vows that a minister of God has not given his blessing to are recognized neither in heaven nor on earth." At his urging, the weeping Lucia agrees to sacrifice herself on the altar in hopes of a heavenly reward. With exquisite timing known only to opera, Edgardo bursts into the wedding assembly just as Lucia has been forced to sign the marriage contract with Arturo. He curses her, demands the return of the ring he'd given to her, and stamps on it. During her famous mad scene following Arturo's murder, Lucia first imagines a formal wedding with Edgardo but then recalls his angry words and his trampling of the ring. She presumably dies of a broken heart during the final scene of the opera in which Edgardo then kills himself at the news of her death.
The goriness of that wedding party is surely equalled by that of Shostakovich's more ghoulishly humorous 1934 Lady Macbeth of Mtsensk, in which Katerina and her lover, Sergei, blatantly marry after murdering Katerina's husband, Zinovy (by a combination of strangulation and blunt instrument), and not at all incidentally also having killed Boris, Zinovy's father (with rat-poison mixed into his dish of mushrooms). During their wedding, a peasant stumbles upon Zinovy's concealed body and sounds the alarm. The local police sergeant is already angry with Katerina for not having invited him to the wedding feast and is only too happy to arrest her and her accomplice, because he hopes that he might thereby gain access to the food and drink! The opera ends with the murderous couple's bitter honeymoon in a dreary Siberian prison camp, where Katerina and a rival for Sergei's affections both die in a tussle, by drowning.
