That was really cool an atmospheric! I'm not sure if it's a boss battle theme, like maybe it could be used in a level, but it's definitely haunting though. This kind of feels like music from like a certain genre of game that I kind of don't remember playing, but I'm kind of getting the feeling I've played this game before with this kind of music.
It's sort of got that industrial rock vibe to it that I'm a pretty big fan of. Like when that higher synth sound comes in, it just kind of builds to the atmosphere and I think it sounds really cool!