This actually references EXTREMELY early EGS.
How early? Things I drew in high school before the comic officially began. So early that it predates the comic as we know it.
Nonetheless, I've always considered it a bit of canon lurking in the shadows that Elliot, Tedd, and Sarah played some tabletop roleplaying games together, and that Elliot was the one running it.
Revisiting that is one of the reasons why I decided this was a storyline I wanted to do.