Shiro BGM

"Castle BGM", titled 「城BGM」 (Shiro BGM, "Castle BGM") in Japanese soundtracks, is a musical theme composed for castle levels in Super Mario Bros. by Koji Kondo. Although the theme has returned in several games since its debut, this theme has been reused and rearranged in far fewer pieces of Super Mario media compared to the other music themes from Super Mario Bros. This makes "Castle BGM" the only theme from that game that has not become a frequently reoccurring musical throughout the series.

Reuses
The following list does not include ports and remakes of Super Mario Bros.

Super Mario Bros. Special
Super Mario Bros. Special features a slightly slower and much choppier version of "Castle BGM" in the game's castle levels.

Super Mario All-Stars
Super Mario All-Stars features an enhanced 16-bit arrangement of "Castle BGM" in Super Mario Bros. and Super Mario Bros.: The Lost Levels castle levels.

This arrangement returns for the same purpose in Super Mario All-Stars + Super Mario World and Super Mario All-Stars Limited Edition.

New Super Mario Bros.
In New Super Mario Bros., an arrangement of "Castle BGM" plays during the Danger, Bob-omb! Danger! minigame.

Super Mario Maker
Super Mario Maker features an ambient arrangement of "Castle BGM" using eight tracks that fade in and out randomly to create a dynamic mix. The arrangement is heard while editing Super Mario Bros.-style castle-themed courses in the Course Maker.

This arrangement returns in Super Mario Maker for Nintendo 3DS and Super Mario Maker 2, where it is used for the same purpose.

Super Mario Maker 2
Super Mario Maker 2 features a arrangement of "Castle BGM" that plays during the nighttime version of castle-themed levels in the Super Mario Bros. style.

Mario Hoops 3-on-3
In Mario Hoops 3-on-3, an arrangement of "Castle BGM", titled 「クッパキャッスル」 (Kuppa Kyassuru, "Koopa Castle") in the game's official soundtrack, serves as the theme for the Bowser's Castle court.

Mario vs. Donkey Kong 2: March of the Minis
Mario vs. Donkey Kong 2: March of the Minis features three arrangements of "Castle BGM" that play during levels in Lava Dome.

Mario Kart Wii
Mario Kart Wiis iteration of Bowser's Castle features a arrangement of "Castle BGM" with  accompaniment and  percussion as the intro of the course's theme, titled 「クッパキャッスル'」 (Kuppa Kyassuru, Koopa Castle) in the game's official soundtrack.

Super Smash Bros. for Wii U
Super Smash Bros. for Wii U features a medley arrangement of various themes from Super Mario Bros., titled "Super Mario Bros. Medley". The medley's intro includes a short arrangement of "Castle BGM", followed by arrangements of the Ground, Underwater, and Underground themes. It was arrangement by the theme's original composer, Koji Kondo. It can be played on the Mushroom Kingdom U and Super Mario Maker stages.

The arrangement returns in Super Smash Bros. Ultimate, where it can be played on any Super Smash Bros.-series and Super Mario-series stage.

The Super Mario Bros. Movie
Two arrangements of "Castle BGM" can be heard in The Super Mario Bros. Movie. In "Strange New World", an elongated arrangement of the bassline from "Castle BGM" can be heard when Toad explains to Mario that Luigi has landed in the Dark Lands. In "Fighting Tooth and Veil", a full orchestral arrangement of "Castle BGM" plays when the cages holding Luigi, Cranky Kong, the Kongs, the Penguins, and Lumalee are being lowered into the lava after Peach loses her Ice powers.

Famicom Music
A arrangement of "Castle BGM" is included in the track "SUPER MARIO BROS (ARRANGE VERSION)" in the Famicom Music album.

Sound Mario Bros.
An arrangement of "Castle BGM" titled 「クッパ・インフェルノ」 (Kuppa Inferuno, "Koopa Inferno") is featured in the Sound Mario Bros. album. The track ends with an arrangement of the Super Mario Bros. version of "Ending".