Ask HN: What's the story behind Bruce Schneier and squids? (schneier.com)

One theory is that it is his way of signaling. (source: https://www.quora.com/Whats-with-Bruce-Schneier-and-squids)

My guess is that he just likes squids, and it is sometimes it is important to step back and do something that isn't super-serious once in a while.