Comic books have quite the variety of means of communicating violent sounds. They’re always in capitals, of course: WHAAAM, SLISH, THUNK, KHWOORMF, AKA-AKA-AKA… really a nearly endless variety of nonce onomatopoeia. It’s the print equivalent of the Foley artist’s job.
You know what Foley artists are, right? They’re those guys who create the sounds you hear in movies and TV shows when assorted things happen – a door is slammed, a person walks up stairs, someone gets punched, a slasher rips someone open… They accomplish some of this with little doors, pairs of shoes on wooden platforms, pieces of wood and/or leather; they also use more organic matter when it produces the best sound. Like in some horror flick. That disgusting sound made when a person is ripped apart might have come from, say, a chicken (ready for cooking) being roughly handled. Imagine the scene of gross horror that could take its sound from a chicken having its backbone ripped out and then slapped flat on a grill.
And now imagine what sound a comic book might use for that sound. Even a comic about a Foley artist. Or perhaps a comic book about a chef. After all, that is a way of preparing a chicken – ripping (or, well, cutting) the backbone out and laying the chicken flat on its inside for roasting. Do it in violent kung-fu style, and you’ll get quite the sound effect:
Which just happens also to be the word for doing that to a chicken. (Butterfly is also used, and what a different word that is!) It’s a kind of preparation method that can produce quick results, since the chicken is flat – you can grill it rather more quickly than you could roast it intact. The whole thing may have a sort of quick-and-messy air to it. Certainly the word does, with the same kind of effect as slapdash or hatchet job. The incoming hiss /s/ has the effect of something speeding towards a surface, and the remaining consonants are all percussive, with a rebounding second syllable, but there’s that affricate right in the middle suggesting a mess…
Small wonder that spatchcock is also used to mean a quick stitch or patch job on something, a slap-together hackle-schmackle – an inappropriate interpolation of material in a text. Slapping it in like slapping a spatchcocked chicken on a grill.
And where do we get this sloppy word? Seems reasonable enough that the cock should refer to a chicken, and, come to think of it, spatch is short for dispatch, isn’t it… Such an easy surmise, so it’s no surprise that it was the commonly given etymology for a long time. But there is no conclusive trail of evidence to prove it. And there’s an older term (at least 200 years older), spitchcock, which is a means of preparing an eel (cutting it into short pieces and dressing it with bread crumbs and herbs). It’s very unlikely that the two words are unrelated, and no one really knows (yet) what the origin of spitchcock was. It’s kind of a mystery – a sort of horror mystery, really. Like from Hitchcock.