Ruben Fleischer's Venom was easily the biggest box office surprise hit of 2018, grossing $855 million from a modest production budget of just $100 million. The superhero movie stars Tom Hardy as Eddie Brock and separates the alien symbiote Venom entirely from his origin story as Spider-Man's nemesis, instead concocting a new origin wherein a group of symbiotes latch on to a Life Foundation space probe and end up crash-landing on Earth.

When it was first revealed that Sony Pictures was working on a standalone Venom movie, most fans were pretty skeptical about the project, since Venom is so closely tied to Spider-Man in the comics. Upon its release, Venom was met with scathing reviews from critics, earning a meager 28% score on Rotten Tomatoes. And yet - against all odds - Venom became one of the biggest box office success stories of the year. How the hell did that happen?

Related: Venom Has Outgrossed EVERY X-Men Movie

Venom Was A Huge Hit Overseas

Three-quarters of Venom's box office total came from international markets - particularly China, where it has so far grossed $270 million, eclipsing its $213 million domestic total. Venom was released in China at the beginning of November and proved to be such a massive hit that it was granted a rare 30-day extension in theaters (foreign movies are usually only granted a month-long theatrical run). Other major overseas markets for Venom include South Korea, where it grossed more than $30 million, and the United Kingdom, where it grossed $26 million. International appeal is now more important at the box office than ever, and Venom nailed it.

Venom Had Very Little Box Office Competition

One of the simplest reasons that Venom was such a big draw at the box office is that it arrived amid a rare drought of superhero movies, and had very little other genre competition. Warner Bros. released only one DC movie this year, Aquaman, and that didn't arrive in theaters until Venom was already out on Blu-ray and DVD. Meanwhile, Marvel Studios' big releases were concentrated earlier in the year, with the final Marvel Cinematic Universe movie of the year, Ant-Man and the Wasp, arriving in theaters a full three months before Venom. Due to release date changes there were no X-Men movies this year, and animated adventure Spider-Man: Into the Spider-Verse came out in the same week as Aquaman.

In terms of direct competition, the only major movie released the same week as Venom was Bradley Cooper's remake of A Star Is Born, which was courting a very different audience. The next blockbuster fantasy/sci-fi movie to hit theaters after Venom was Fantastic Beasts: The Crimes of Grindelwald, which didn't arrive until six weeks later. With general audiences hungry for superhero movies, and very little else on offer, Venom was suddenly the hottest ticket in town.

Venom Had Strong Marketing & Word of Mouth

A considerable portion of Venom's success can be attributed to the way it was marketed around the star power of Tom Hardy and the unique character design of Eddie Brock's extra-terrestrial stowaway. In China, Venom was promoted with a hilarious cutesy campaign that showed all the reasons why Venom could be a perfect boyfriend (see above). A movie that could have gone down the potentially disastrous route of being promoted as a dark and edgy antihero movie was instead billed - by critics and fans, and eventually by Sony as well - as a buddy comedy or rom-com.

While even those who enjoyed it would probably agree that Venom isn't a good movie, it was certainly an entertaining one. It embraced its own ridiculousness and Hardy threw himself wholeheartedly into the role, including a memorable improvised scene where Eddie climbs into a lobster tank at a fancy restaurant to cool down and starts eating live lobsters. By the time the home video release marketing rolled around, Sony had completely embraced fans' interpretation of Eddie and Venom's relationship as romantic, and the official Blu-ray trailer humorously presented the movie as a romantic comedy. Add in a tie-in song and music video from Eminem, which currently has almost 200 million hits on YouTube, and Venom absolutely maximized its selling power.

More: Screen Rant's Top 10 Favorite Movies of 2018