It’s difficult to get that mix of “creepy”. It sounds like it should be easy – a low throbbing undercurrent, maybe a few other little grace notes of sounds thrown in.
But in my experience, many musicians try… and fail to hit the mark. Either the throbbing becomes so insistent that it almost becomes lulling, or the other sounds (let’s call it “melody” for convenience) is so noticeable that it ceases to accentuate the desired mood, instead becoming the mood.
The Cryo Chamber Collective has two albums out – evocatively titled “Cthulhu” and”Azathoth” that manage to strike this balance well. There’s enough texture that the tracks do not become boring and monotonous, just a light enough touch with the “melody” that you’re not constantly questioning “What was that?”