Substitute the dictionary with your own imagination!
I first played the word game "Balderdash" in Grade One. In Grade Seven, I had a group of younger kids that I mentored, and I revived "Balderdash" as an ELA exercise for them.
Quite simply, in "Balderdash", I - as the first author - will make up a word in my title. For the body of my chapter I will then define my made-up word, and possibly even include a history (making my dictionary entry more like an encyclopedia entry).
Following that, I will create up to three more nonsense words which will serve as the title of the next branches (excluding me, the first author, everyone only gets to name branches others will write, not their own).
This might sound confusing; this might sound difficult, or merely childish. Whatever this turns out to be, I hope that it might catch on as just something fun for Protagonizers to do.
As I've already stated, I will start, in order to provide an example for any future collaborators...