[UPDATE: Big thanks to commenter SKFK, who tells us that the story is called “Bongcheon-Dong Ghost” (Bongcheon-Dong was the name of a poor area of Seoul, since renamed to avoid past negative associations), and was written and illustrated by Horang (the pen name of 25-year-old cartoonist Jong-Ho Choi).]
...and that's about all I can say about it, really: This is a very scary webcomic. The text of the strip and the site on which it's found is in Korean, which I cannot read, and Google Translate doesn't clearly indicate an author or title, nor translate the text in the comic itself. But the content is crystal-clear even despite the language barrier. As Batman Incorporated artist Chris Burnham (through whom I found the comic) put it, "The pictures tell the story." And the story, about a girl walking on a deserted city street who sees a strange-looking passerby in the distance, is scary as hell. Like Emily Carroll's "His Face All Red" before it, this comic uses the unique properties of the web (albeit in a totally different way -- you'll see when you read it) to deliver an intensely uncomfortable experience. Read it yourself, preferably with your speakers on and nothing you can't afford to drop in your hands.
Meanwhile, if any Korean readers or manhwa fans out there can help us out with the creator, title, and translation of the comic, please let us know in the comments below.