It's been a decade since Dr. Horrible's Sing-Along Blog took the internet by storm with Neil Patrick Harris as the web series' lovable singing supervillain. Joss Whedon's three-part musical wasn't the very first digital experiment of its kind. But along with Dr. Horrible star Felicia Day's crowd-funded web series The Guild, it was among the first to show how content made specifically for the internet could be successful.

Ten years later, fans are still performing their own versions of the saga and cosplaying as Dr. Horrible and his nemesis Captain Hammer (played by Nathan Fillion in the series). Whedon said he thinks Dr. Horrible would probably still be a big success if it were released today; it just wouldn't be as special.

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"It definitely wouldn't surprise people as much as it did, because there have been a lot of things since then in that territory. And we're all conversant in social media and computers in a way that we weren't then," he told Polygon in an anniversary interview. "[Dr. Horrible] might be bigger, and people would be like, 'Oh good, make more!', and we could. But I think it wouldn't have been — we wouldn't have been pioneers if we let somebody swim over first. Not that the people didn't, because Felicia definitely did. She was definitely on a boat before the Mayflower."

Now, after more than a decade of waiting, fans will get to return to the world of Dr. Horrible's Sing-Along Blog in a one-shot comic from Dark Horse, titled Dr. Horrible: Best Friends Forever. Whedon's pitch for the cover brings Dr. Horrible and Captain Hammer together as alleged best friends. It also teases the return of Penny, who died at the end of the web series' third episode — but in a dream sequence.

"Usually I'm insane about structure, but was like, 'I know how I want to start.' And then it just kept unfolding. And it really unfolded in like, 'Oh, this is a very classical structure, and here's where the dream sequence goes, and here's why it's in there. Oh, and it's sort of sad! I can make it a little depressing too. Put a little of that flavor in there.' After 20 pages of idiotic jokes," Whedon teased to Polygon. "It was a lovely process of just hearing these guys talk to me again and just going off. I don't get to be that silly very often."

Dr. Horrible: Best Friends Forever is available now for digital purchase.

<p>Neil Patrick Harris, <em>Dr. Horrible's Sing-Along Blog</em> </p>

Neil Patrick Harris, Dr. Horrible's Sing-Along Blog