Lesson learned... HC
I recently found out you could export chars to single player to try out stuff like bossing so I gave it a shot. Exported char to single player and then I logged in, BUT I didn't realise I went online by habbit of opening the game.
So I went off killing mini-ubers and then opened up uber trist. Killed meph in 5sec, then Baal and Diablo were after me but my Sin was pretty tanky so she could handle both. Baal died and very little life remained on Diablo so I stepped away for a sec to escape game and try it online without too much care. Diablo's lighning smacked me while I was slowly escaping - and I didn't care much because I though I was in SP until I died...
That is when I thought : ''Was that SP or did I just log in as usual?'' The later was true and I find myself grinding with another char now.
All hopes of reaching 99 with a char are gone for the season, but it was yet another lesson learned in this game - Make sure you really are in SP if you want to mess around with some bosses y'all !