16.8.5

16.8.5 is a story written by Kawahara Reki that was published on one of the Story Clear Files that are specially made for the Dengeki Fighting Fair in 2014. Each author has to write their own story with evolution as the theme and their work is published on the back of some clear files that have an illustration drawn by the original illustrator for the series on the front. The SAO version of this file is available as of August 2014. To get this publication, customers have to visit one of the bookstores that have joined the activity and follow the way set by each individual bookstore.

Summary
The story's theme would be "evolution", like any other work in the same series, and it is about "teeth brushing" according to limited amount of available information.