I've lurked around here for a while, originally coming for CWC coming back for a few Deviantart cows and Springtrapp/Ashley.
I finally made an account because there's a sperg that has run rampant for months that I've had many run ins with. His name is Xandermartin98 and I'm not sure if anyone here knows him. He's little known, although I guess that's because he's mostly within the Undertale fandom. He stands out as particularly bad which is saying something when you're dealing with Undertale fans. He's also quite literally autistic.
Xander is creepily obsessed with a cartoon lizard from a video game named Alphys, who he wants to fuck. He writes awful fetish fanfictions about her, and created a "shipping" (fan pairing) of her with some other creatures from the game that are essentially other characters melted and stuck together (the ship is called "alphamalg"). Sometimes he'll involve other source material into them but most of the time they're Undertale-related. He cranks these things out like crazy.
The worst part is he goes on places like reddit and deviantart and whores out his fetish fanfictions. Xander posts them on completely random subreddits to the point where it seems like he gets off to showing people this shit. He spammed them on the Undertale Cringe subreddit until he got banned, which caused him to start harassing people there with alts and teamed up with some other autist to take the owner's account and destroy the subreddit. Whenever he gets banned from anywhere he'll instantly start up an alt account and keep on spamming. He has been doing this for months; he'll disappear for a month or so, and just when people think he's gone, he'll come back.
He's absolutely everywhere. Reddit, Deviantart, YouTube, even fucking Rule 34.
And before all this Undertale shit started, he did this same thing with Cave Story, apparently. He was well-known on the forums.
His Deviantart was banned I believe, but he also used to post shitty art. He was also suspended on reddit.
His fanfiction:
https://www.fanfiction.net/u/5606545/xandermartin98
Some reddit alts of his (main one is suspended, it was Xandermartin9

:
https://www.reddit.com/user/Darkrai9000/
https://www.reddit.com/user/Darkrai9OOO/
His Youtube (nothing much here except some low quality videos but you can see him):
https://www.youtube.com/channel/UCRtO18ARrcfmqhxrBDJdzMw