This template takes a string with wiki links in it, and then separates the wiki links out one at a time, and puts their subject (either before the ]] or the |) into a category like so:
If [[Hellboy]] is entered, [[:Category:Hellboy/Appearances]] is returned.
If [[Big Red|Hellboy]] is entered, [[:Category:Big Red/Appearances]] is returned.
If [[Hellbot]] is entered, [[:Category:Hellbot/Appearances]] is returned. (like a spelling error)
Anything that is not a link is ignored. This template is designed to be used with the Comic template, to auto-categorize the people, teams, locations, etc. that appear in the comic.