What do they do?
I've only heard of them because I got beat bad by someone who had one.
It adds 15 more whole points to each stat. Probably a good rule of thumb would be to never fight someone who has one, unless you're really confident that you can smote them. At least for now. (not that someone with a Mr. A. can't be beat, I've done it, but you really have to be good to do it)