'The Arm' is a disembodied harbinger of death, from what I can gather, which turns the protagonists' partner into 'a lifeless carcass in a badass car crash.' It's the 'badass' that stops the line from being morbid, and that makes the rhyme. The use of 'badass' to defuse what was almost a truly gruesome image has been a signature Thorburn move since the Unicorns. Change up the hooks before they get old, interrupt sentiment with absurdity, cut a letter off the front end and make the cliches new. -paperthinwalls.com