It's bedtime. The characters are getting ready for a good night's sleep or have already drifted off to dreamland. The soundtrack in this case completes the mood, playing a soft, light melody akin to a lullaby, as though singing the characters to sleep. There may be actual singing, but for this to be in effect, it should be part of the soundtrack, rather than source music.
Instruments used are typically ones with soft, soothing sounds. Some of the more common ones are the celesta, glockenspiel, or toy piano, probably for their sound invoking that of a music box.
A couple of likely Standard Snippets are Brahms' "lullaby"
and "Rock-A-Bye Baby".
Compare Nostalgic Music Box. Contrast Rousing Lullaby and Ominous Music Box Tune.
Examples:
- If a song in an anime soundtrack has the word oyasumi (meaning "good night") in the title, there's a good chance it's a lullaby (at least if it's a Kodomomuke show). For example: the Japanese ending theme for The Littl' Bits is called "Oyasumi Chuchuna" (translating to "Goodnight Teenybit," using the English name for that character) and is a lullaby for the male lead's baby sister. Likewise, the original Maya the Bee series ending theme is a lullaby to the titular character: "Oyasumi Maya."
- In the Onbaa filler episode of Naruto, a calming music box rendition of Tenten's theme when the Onbaa bring a passed-out Naruto back to the Hidden Leaf Village near the end of the episode.
- Tarzan: "You'll Be In My Heart" starts as Kala singing to Tarzan, then switches to Phil Collins for the rest of the song as the gorilla tribe settles down into their nests for the night.
- Raiders of the Lost Ark: After retrieving the ark from the Nazis, Indiana Jones is getting an After Action Patch Up from Marion which leads to the two starting to get amorous, the orchestra building up the Love Theme before...it trails off with a celesta as Indy's exhaustion finally catches up with him.
- Jurassic Park: The track "A Tree For My Bed", basically the main theme played on a celesta, plays as Grant and the kids are settling into the (relative) safety of a tree for the night.
- The Champ: At the end of the film, as Dink sobs into his mother's arms following Champ's death, "Brahms' Lullaby" starts to play over the end title.
- Babylon 5: "The Parliament of Dreams" begins with G'Kar singing to himself as he prepares dinner right before being informed that an old political rival has sent an assassin after him. Later, he is informed that the assassin's guild would have left him a black flower as a warning, and that if he hasn't received one, he can rest easy. That night, G'Kar is sleeping in bed while the soundtrack plays a lullaby version of the song he was singing before turning into something more akin to horror music as he awakes to find a black flower lying next to him.
- The Big Comfy Couch: Each episode ends with Loonette and Molly going to sleep with an instrumental lullaby version of the theme song playing over the end credits.
- The NCIS episode "Jack Knife" has an exhausted McGee on the verge of falling asleep several times; each time, the soundtrack plays an off-kilter version of "Brahm's Lullaby".
- Super Mario 64: If you approach a sleeping piranha plant, the main soundtrack fades to a soft lullaby tune.
- Ace Attorney Investigations: Miles Edgeworth: Cammy Meele is a witness who constantly falls asleep. Naturally her theme is half asleep itself.
- In the online game Kindergarten, "Rock-a-Bye Baby" plays whenever one of the children sleeps.
- In Betty Boop, the episode "More Pep" focuses on Betty and an offscreen guy named Uncle Max trying to make Pudgy the dog more energetic. Pudgy keeps falling asleep and whenever he falls asleep, "Brahms' Lullaby" plays.
- In Animaniacs, when the Warner siblings fall Asleep in Class, "Rock-a-Bye Baby" plays in the background.
- In The Loud House episode "Two Boys and a Baby", a lullaby tune plays whenever Lily falls asleep.
- 2 Stupid Dogs: At the start of "Bathroom Humor", "Brahms' Lullaby" plays while Big Dog is asleep with his head in a trash can.
- In one of the animated episodes of The Berenstain Bears, Raffish Ralph is meeting with Weasel McGreed about his latest plan to take over Bear Country, which involves hypnotism. Weasel demonstrates by hypnotizing Ralph to sleep, which is accompanied by a statement of "Rock-a-Bye Baby" on the saxophone, the main instrument of Ralph's Leitmotif.
- Non-sleep related: the Bugs Bunny cartoon "A Feather In His Hare" ends with the Mohican collapsing in a dead faint when he sees storks above carrying his newborn triplets, then Bugs follows suit when he sees storks carrying a massive litter of newborn kittens (baby rabbits), all this to Carl Stalling's arrangement of "Rock-a-Bye Baby."
