Things such as a soloist's instrument breaking mid-performance, chandeliers falling from the ceiling, a performer's hair catching fire, the conductor falling off the podium, etc. Something that had a significant impact on the performance, with the critics giving it a 0/10!
Also, I'm thinking mainly of performances by the more known composers (J.S. Bach, Mozart, Vivaldi, Handel, Schubert, Haydn, and so on).
There's so many historical examples of failed premieres this probably should be removed for being a trivia-seeking question! But here's a story from Baroque times, and a French premiere that went badly for Wagner, and then as a contrast far and away the most successful opera of the Baroque period, which you've likely never heard of. If you want a book just of these Great Operatic Disasters is a fun read. /u/erus might also have some non-opera examples in his comment history if he has time to pop in here.