Omega Metroid Territory

"Omega Metroid Territory" is an unnamed theme from Metroid II: Return of Samus. It was composed by Ryoji Yoshitomi.

Description
This theme is played throughout the second half of Phase 8, where Samus Aran faces the final three Omega Metroids. It continues to play in the yellow liquid-flooded tunnels and caverns of Phase 9, as well as a few rooms of the Chozo ruins where Samus can obtain the Ice Beam or replenish her energy and missiles.

This theme is considered one of the most dark and menacing themes from the game, notable for being one of the few melodic area themes. The melody is set in a lower register and played in a minor key, giving it a villainous tone. Approximately every six seconds, a heavy echoing beat is heard; this is not in sync with the song's tempo, and therefore makes each loop sound slightly unique. The theme can be heard here:

In Metroid: Samus Returns, this theme was effectively replaced with Chozo Laboratory and Area 8. It is not confirmed if any songs in this remake were intended remixes of this theme, but there are a few notable similarities that suggest that Daisuke Matsuoka may have been influenced by this track. Area 6, which likewise can be heard in Omega Metroid territory, has a short flute melody that bears striking similarity to part of the original track's melody. Some of the high-pitched strings of Boss Omega are also very similar to another segment of this theme.