Music is an interesting one. There's a lot of subjectivity in the understanding of music, but there are some very basic principles that seem near-universal in

Music is an interesting one. There's a lot of subjectivity in the understanding of music, but there are some very basic principles that seem near-universal in human cultures at least. Octave equivalence, the consonance of small-number frequency ratios. Presumably aliens wouldn't experience music the same way we do, especially if they don't have ears or physical bodies. But music itself might be interesting to them even if they don't really "get" it, due to the mathematical relationships involved. And they might have something analogous that we can't fully understand. On the other hand it's also at least possible that aliens would understand our music perfectly well, and find it boring or atrociously bad due to our obliviousness to phase relationships, or the inherent out-of-tuneness of modern music, or how the tempo of the music is untethered from its pitch, or because our range of human hearing misses out on all the good stuff that happens above 15-20khz.