Matad Ambi

This article is written from the Real Life point of view

"Space Pirate encrypted data decoded."

The subject of this article is not named in-game.
The current title is from the game's internal data.

Matad Ambi (as named internally) is a melancholic-sounding, ambient theme in Metroid: Samus Returns. It was composed by Daisuke Matsuoka.

It is heard after Samus Aran drains any cavern containing purple liquid by using a Chozo Seal, permanently replacing M2 Ancient Chozo Ruins Arr in that area. It will play immediately after the Matad Jinchozo jingle (which plays when the liquid lowers) stops, and cease when Samus boards the elevator to the next area. It is always heard in the drained caverns on subsequent visits.

The theme can be heard here.

Trivia

Due to the lack of a Chozo Seal, Area 8 is the only area of SR388 where Matad Ambient never plays.
The word "Matad" is a reference to "Project Matadora", the development codename for Samus Returns, while "Ambi" is most likely short for "ambient" or "ambience".