Trying to determine if this sentence needs a comma; in my head it does, but I can't articulate why
"His neck took to what had become apparent its characteristically unnatural bend."
In my head, this needs a comma after "apparent," but I'd like to know with certainty whether it is necessary and, if so, why?
The sentence is definitely wrong. It should read
His neck took to what had become apparent was its characteristically unnatural bend.
And a comma anywhere in there would be wrong.
If you really want commas in there, you can do it like this:
His neck took to what, as had become apparent, was its characteristically unnatural bend.
But that sounds even clunkier to me.