Author here! To be fair, there is no particular backstory. I picked a hermit crab as the book logo since crabs are strongly associated with Rust due to Ferris,

Author here! To be fair, there is no particular backstory. I picked a hermit crab as the book logo since crabs are strongly associated with Rust due to Ferris, Rust's mascot. I then landed on that style (and the skull) because they looked sick and distinctive. The cover images of many technical books are incredibly dull these days.