A cute little creature is climbing to the top of the Japanese box office. Chiikawa The Movie: The Secret of Mermaid Island has become a massive hit, grossing 6.77 billion yen (roughly $43 million) in just 17 days. That makes it the fourth highest-grossing movie of the year in Japan, behind only Michael, Toy Story 5, and Detective Conan: Fallen Angel of the Highway. The movie got off to a fast start, making over $6.2 million on its first day, the seventh-highest opening ever for a film in Japan. It has made over $280 million worldwide so far.

For those who’ve never heard of the Chiikawa series, it originated as a Twitter web manga by the artist Nagano. From there, it was collected in eight volumes by Kodansha, which have sold over 3.6 million copies as of November 2024. The anime from Doga Kobo has run since 2022, totaling 367 episodes (each is one to two minutes long).

The series follows Chiikawa, a little creature that resembles a hamster or mouse. They go on adventures with their similarly adorable friends Hachiware (who looks like a cat) and Usagi (who looks like a bunny). However, where things get a bit weird is that, in addition to being described as a “comedy” and “slice of life" story, as you would expect, the series has also been labeled a "dark fantasy."

The manga has been described as a critique of the gig economy, as the main character is frequently forced into dangerous life-or-death missions involving monsters. Adorable creatures are killed, and Chiikawa is nearly eaten. There is also body horror, with cutesy animals becoming permanently transformed into beasts called chimeras. These moments stand out because the majority of the series is made up of the kind of cute shenanigans you'd expect.

Chiikawa The Movie: The Secret of Mermaid Island adapts one of the series’ darkest arcs, involving murder and folk horror. Children have reportedly burst into tears during the film, and some took to X to post genuinely unhinged tangents about the movie that have further stoked curiosity in regions where it hasn’t been released yet.

While HIDIVE used to stream Chiikawa in North America, it no longer carries the anime. Amasian has a few episodes streaming for free, but it doesn’t appear that the full show has an official English-language translation. Perhaps morbid curiosity around The Secret of Mermaid Island will result in the series getting a wider release so we can all enjoy its pint-sized horrors.