The Music Layer
This is an earworm New layer of our brain, like a subsystem, that constantly plays a soundtrack (or 2) in our shared space like it's over a PA system.
We think there's at least 2 entities in this layer: one plays music (usually snippets over and over again) all day. The other, louder and more intrusive, makes up words to songs to fit the current situation. Sometimes it gives us a "song starter" and we grab it up and run with it changing the rest of the words of the song with it. But usually it just functions without interactions at all.
Thankfully our earworms respond well to external music. We can get past a stuck snippet by playing the song and sometimes by playing a different song.