Someone who reads, or is an avid (or sometimes rabid) fan of the Homestuck/Hivebent webcomic drawn/written/animated by Andew Hussie as seen on his website, MSPA, or MS Paint Adventures.
Often this term is used to describe the more dedicated fans who might be seen drinking faygo, saying "honk," "shoosh-papping," wearing colourful zodiac shirts, wearing handmade horns in candycorn colors, or spending their free time drawing shitloads of fanart of their headcanons or ship pairings.
Me: I just spent the entire weekend drawing EridanxFeferi fan art and I ordered my Aquarius shirt... Am I a homestuck yet?
Friend: ...We are no longer friends.
Me: *sobs in a corner*