Well, in my opinion, the most cancerous fandom doesn't really exist. Every fandom has that one person who:
In the end, I don't really care about fandoms. Like whatever you like, folks. Just don't be an asshole.
- writes bad fanfiction
- draws r34 and/or fetish art
- starts flame wars
- is more toxic than poison
- is just a plain old asshole
..But if I had to choose, then here's my little list. (Note: this list is not in a particular order.)
- Markiplier/Other Youtubers: I have nothing against Mark, after all, he has done lots of charity work and he's a nice guy overall. (Though, I don't watch his channel.) But, his fangirls are completely rabid, they literally obsess over this guy. Some fangirls call him daddy, wtf?! Actually, this could fit with most Youtubers like Dan and Phil, Game Grumps, Superfruit, and more.
- FNAF: Need I say more?
- Call of Duty: Uh, I'd rather not hear bunch of screaming 13 yr olds who just figured out what swear words are.
- Tumblr: Do you wanna be in a minefield of annoying feminazis? Then check out Tumblr! To be fair, there are a lot of good art and good photography on tumblr, but my point still remains. Also, the people who obsess over youtubers are here too.
- Homestuck: Again, need I say more?