Experimental Industrial / Noise.

In my youth, my father would come into my room and would ask where that noise came from, and he flat out refused to believe me when I said that was music.

One example would be Parca Pace - Topic.

Download also has a lot of tracks that my father would not recognize as music, like The Eyes of Stanley Pain.

Of course, if you are reading this, then none of this might be particularly niche to you.