Here's me trying to laugh through my anxiety attacks. Most of my immediate family has dealt with anxiety disorders; I've fought them since I was 13. At the most anxious periods in my life, I have experienced hallucinations, many involving spiders. This is not hypnogogic / hypnopompic, which occur during sleep or awakening -- this was during regular daily activities.
During a particularly tough stretch in 2002-2003, I was rather frequently hallucinating that the people around me were turning into person-sized spiders, wearing clothes, often driving oncoming cars. One day after such an episode, Bowie's "Ziggy Stardust" came up on shuffle play, and after David sang the line that became this song's title, I laughed. A lot. For several minutes. Where WEREN'T the spiders? So I started writing a list of where the spiders were.
I wrote the chorus/turnaround in '09 to finish it.