Songs used to be short, then they became longer, and now they're getting shorter. But otherwise, music is about a beat and a message. If the beat gets to the audience, and the message touches them, you've got a hit.
The juvenile sea squirt wanders through the sea searching for a suitable rock or hunk of coral to cling to and make its home for life. For this task, it has a rudimentary nervous system. When it finds its spot and takes root, it doesn't need its brain anymore so it eats it!