Sorry I accidentally deleted my last post. I appreciate the answers the two people gave.
This is some big larva I found and the head looks centipede-ish but the body is short and fat with less legs.
I went through my images and found an old photo of a beetle that was on my screen door. Maybe it's a larva for one of these?
Last night there was a post about this. According to the post, at the time of naming "cock" was a word referring to size and "chafer" is the type of bug.
I did not fact check this, but it is an explanation I find preferable to the alternative.
edit: The name "cockchafer" derives from the late-17th-century usage of "cock" (in the sense of expressing size or vigour) + "chafer" which simply means an insect of this type, referring to its propensity for gnawing and damaging plants.