Which one is the original One Punch Man, the webcomic or the manga?
Firstly, the Manga isn't headcanon (Note:A lot of fan made manga does exist). It is a detailed redrawing of the Webcomic, with extra chapters occasionally drawn in. The Webcomic is way ahead and is more or less the same, word-for-word if compared to the completed chapters of the manga.I personally recommend reading the manga first and then continuing with the webcomic. However, the webcomic tends to deliver its humor a lot better because of the ridiculous art style.