A fan of the popular webcomic 'Homestuck' who makes other fans ashamed to be of the same species. Often refers to a poorly made, obviously effortless cosplay, in reference to an incident in which a Homestuck at a con supposedly tried to die her skin grey for a Terezi cosplay by filling the hotel bathtub with black and silver sharpies and bathing in it.
All she got from that was ink poisoning, and removal from the hotel.
Also can refer generally to ANY 'bad' or embarrassing Homestuck fan- fans who are rude to non-Homestucks, take things to their far extremes, misunderstand and twist the comic, apologize for the villains and try to excuse their wrongs, harangue people to read, and force their fandom down others' throats. Anyone who skips to Act 5 for the trolls is a sharpie water.
Homestuck 1: "I found out today that Rebecca didn't even read the first four acts of Homestuck, she skipped to Act 5 because she thinks it's the only good part."
Homestuck 2: "Ugh. What a dumb sharpie water