...Wait, is this for real? Did Kogasauthor really have a period where he looked like Sadako?
From the strip title, he apparently once let his hair grow out for about five years. Whether this was enough for him to do a Sadako impression is debatable unless he also shares those photos online, but I'd say the difference in his hair length between then and now at least made that sort of impression, even if it wasn't actually THAT long.
5 years without having a haircut should be enough to have hair as long as what is shown on strip, even 2 years without a haircut can give you a fairly long hair.
Don't you ever grow out your hair, Kogasa?Really!?You don't have pictures, do you!?