Laughing Gas is a 1936 novel by P. G. Wodehouse.
It doesn't star Jeeves and Wooster and it isn't set in Blandings Castle. Instead it is a one-off story starring Reginald "Reggie" Swithin, the third Earl of Havershot. Reggie, who has recently inherited the earldom at the age of 27, is informed by his attorney that he is now head of the family. As such, he's responsible for the whole family—so he has to go to Hollywood. It seems that his alcohol-soaked cousin Eggy is in Hollywood, and Reggie's Aunt Clara is deathly afraid that her son will marry some gold-digging American commoner.
Reluctantly but out of a feeling of obligation, Reggie departs. On the train headed west, he meets film actress April June, and is instantly besotted with her. At one of April's Hollywood parties he runs into Eggy. It seems Eggy is engaged to Ann Bannister, Reggie's former fiancee, who broke up with him two years ago. Reggie clearly has unresolved feelings for Ann, but he's now in love with April June, so he takes it in stride.
Meanwhile, Reggie gets a toothache and needs his tooth extracted. He goes to the dentist and there meets a bratty child actor named Joey Cooley, who also has a toothache and needs his tooth extracted. Reggie isn't very impressed by the pint-sized movie star, but it doesn't seem to matter much as they're both taken in to separate rooms to get their teeth pulled. However, when Reggie wakes up from the gas, he finds out that, somehow, his and Joey's souls have switched bodies.
- The Alcoholic: Eggy, who drinks constantly. He quits cold turkey, however, after one too many encounters with Reggie in Joey's body makes him think that he's hallucinating.
- Continuity Nod: Most of P.G. Wodehouse's fiction was in a shared universe. He joined this book to his other writing by making Reggie a member of the Drones Club, of which Bertie Wooster was also a member.
- Contrived Coincidence: Reggie travels from England all the way to Hollywood, where he meets his old girlfriend Ann Bannister, whom he last saw two years ago and a whole continent away at Cannes.
- Fainting: April June faints when Reggie describes the boxing match he attended in Chicago. She's faking.
- "Freaky Friday" Flip: The central premise, as strange dreams while they are knocked out by laughing gas cause Reggie and little Joey to switch bodies. Reggie is not at all happy about it, but Joey, who is sick and tired of being a child star, is pretty pleased to instantly become a rich grownup. Reggie's narration makes clear that this was already a well-worn trope by the 1930s, as Reggie is familiar with the idea and muses about how in fiction, the people who fall victim to this are never believed. (The trope actually dates to an 1882 novel called Vice Versa.)
- Gilded Cage: Reggie is unhappy to find that Joey Cooley is basically held prisoner at the home of studio head T.P. Brinkmeyer and his awful sister Miss Brinkmeyer. He's fed a diet that's mostly stewed prunes and some sort of "sawdust" breakfast cereal, he's scolded relentlessly by the tyrannical Miss Brinkmeyer, and he's forced to do things like kiss the middle-aged ladies who run his fan clubs.
- Gold Digger: April June, who wants to be a countess and so sinks her hooks into gullible Reggie.
- Love at First Sight: Reggie has his heart set on marrying April June within hours of meeting her. Of course, she is a good-looking actress who is putting on the full-court press in an effort to ensnare him.
- Magical Realism: While the rest of Wodehouse's books and stories all had quite silly plots with all sorts of unlikely things happening, they were all grounded in reality. This novel on the other hand has a "Freaky Friday" Flip come out of nowhere, turning the story into a fantasy set in 1936 Los Angeles.
- Narrative Profanity Filter: Ann says Reggie is only asking to marry her out of pity. Reggie responds with what sounds like a Precision F-Strike."I said something about pity and charity so crisp and incisive and so wholly unfitted for the delicate ears of woman that even in the midst of her emotion she gave a little startled jump."
- No More for Me: Eggy the hard drinker initially blows off the temperance lady's warnings of Pink Elephants, until Reggie (as Joey) appears in the house and Eggy begins to think that Reggie is a Pink Elephant. When Reggie (as Joey) tells him who he really is, a horrified Eggy swears off drinking and joins the temperance lady's church.
- Separated by a Common Language: A panicky Reggie (in Joey's body) explains his predicament to Ann, who says "Yes, you're certainly in a swivet." Reggie follows that up in his narration by saying "The word, I took it, was American for 'soup'."
- Title Drop: "Laughing gas", aka nitrous oxide, which Reggie takes when getting his tooth pulled at the dentist. After a weird hallucinatory dream Reggie wakes up to find that he and Joey have switched bodies.
- The Tooth Hurts: Reggie gets a bad tooth and has to have it pulled. This leads to a series of bizarre events as he experiences a "Freaky Friday" Flip with another patient.
- Ugly Guy, Hot Wife: As Reggie himself admits he has a face like a gorilla. This makes him insecure, and easy prey for April June. It also makes him hesitant to admit his feelings to Ann at the end.
- Yellowface: The Japanese gardener who gives Reggie a bucket full of toads turns out to be an actor in makeup who is trying to get Brinkmeyer the film mogult to hire him.