Well....... Oh no..... It's gonna be a tough contest here. I have an unusual talent for going viral in ways that in no way benefit me.
IN THE ORANGE CORNER! We have this goddamn flowchart I drew at 11pm one night in a bad mood, dumped on my Tumblr and went to bed and it ended up with hundreds of thousands of shares there, but then also people started reposting it without my permission on 9Gag and stuff where it got literal millions of interactions, and it keeps turning up on my timeline. The worst is the horrible line-smoothed version where they changed the lines to black with auto trace. Hundreds of people have this printed out on their walls, and I've seen multiple people selling it on merch. It's never made me a single penny. AAAAGH.

IN THE BLUE CORNER! We have this tweet I made that oh my god keeps turning up in screenshot form on every D&D community in existence. Even Matt Mercer gave it a like. At least my name is on this one? The actual tweet only has about 8k retweets, but the screenshot of it turns up a lot, so I get tagged on Facebook a few times a year by friends who just got into D&D going "OMG KATE, IT'S YOU!?"
AND THEN THERE'S THIS SURPRISE GUEST CHALLENGER!!!!! So I saw on twitter that a little girl had drawn a Hearthstone card and I was bored and sad and felt like my life was going nowhere so I was like "I'm gonna do a quick repaint of this card like it's a real Hearthstone card! Then uh.... The guy in charge of Hearthstone at the time shared it and I got interviewed by Kotaku, so I can't really guess the extent of it.
https://twitter.com/i/events/973609158191628288
This one is the closest thing to an actual damn drawing I've ever gone viral with 