* ActorSharedBackground: Creator/AlysonHannigan maintains that she cannot sing or dance (which hasn't stopped multiple writers from shoehorning her into [[Series/HowIMetYourMother splashy musical numbers]], but oh well), and requested her part in "[[Recap/BuffyTheVampireSlayerS6E7OnceMoreWithFeeling Once More With Feeling]]" be limited.
* CompletelyDifferentTitle:
** French: ''Billy''
** German: "Die Macht der Träume" (''The Power of Dreams'')
* DeletedScene:
** A line of Xander's was cut from the original script due to length:
-->Okay, despite the rat-like chill that just crawled up my spine, I'm going to say this very calmly: Helllppp ...
** An exchange between Giles and Buffy was also cut from the original script due to length:
-->'''Giles''': Are you all right? You look a bit piqued.
-->'''Buffy''': Hospital lighting. It does nothing for my fabulous complexion.
-->'''Giles''': Are you... sleeping all right?
-->'''Buffy''': I'll sleep better when we find this guy. Nothing like kicking the crap out of a bad guy to perk up my day.
* EnforcedMethodActing: Creator/SarahMichelleGellar has the same phobia as Buffy, which made filming this episode specially difficult for her.
-->I have an irrational fear of cemeteries and being buried alive. I told the producer, "Look, I can't do it, I'm sorry". Through miscommunication, the message never got relayed, and it was four in the morning, and they basically made me do it, and I was hysterical. It was one of the hardest things I've ever done for my job, ever. Some people find cemeteries a turn-on. Some people like sex in cemeteries. Not me. I cried the whole way home. It was horrible. It's really hard to be a vampire slayer if you're scared of cemeteries.
* SimilarlyNamedWorks: There is also a chapter of the ''WesternAnimation/TurningRed'' fanfic ''Fanfic/ThePandaChronicles'' named "Nightmares".
* ThrowItIn: Willow running off the stage during the end credits scene was improvised by Creator/AlysonHannigan.
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