Chiikawa's first theatrical anime feature, Chiikawa the Movie: The Secret of the Mermaid Island, opened in Japan on July 24, 2026, and has become a major box-office hit. Nearly one month into its theatrical run, the film is now closing in on the 10-billion-yen milestone.
On August 17, the official account revealed the film's third admission bonus: the “Happy Siren♪” pull-back car. The toy features Siren carrying Chiikawa, Hachiware or Usagi on its back before racing forward, and will begin distribution on August 22. The announcement immediately sent fans into a frenzy, with reactions including, “Three Sirens at once is honestly terrifying.”
The “Happy Siren♪” toy is a pull-back car that sends Siren speeding forward once it is pulled backward and released, recreating the sense of speed seen in the film. There are three versions in total, featuring Chiikawa, Hachiware and Usagi riding on Siren's back, with one version distributed at random to moviegoers.
Even better—or perhaps more ominously—the bonus was personally conceived by original creator Nagano. An accompanying illustration shows Chiikawa, Hachiware and Usagi each riding one of three Sirens at full speed, while the islanders and Shimajiro react with everything from tears to outright shock.
The contrast is especially funny: Chiikawa is crying in fear, while Hachiware and Usagi gleefully shout about how fast they are going. It's exactly the kind of delightfully unsettling humor fans have come to expect from Nagano.
Once the post went live, fans quickly flooded the replies with comments such as: “So Nagano-sensei personally came up with this bonus...,” “Wait, does this mean there were actually three Sirens all along!?,” “The islanders are in absolute hell, that's brutal,” “They really made Chiikawa cry in the official illustration...,” “How else are you supposed to describe three Sirens other than terrifying?,” and “Of course Hachiware is the only one completely unfazed（笑）.”
The replies were packed with the kind of darkly affectionate jokes longtime Chiikawa fans know all too well. It seems Nagano knows exactly what the audience wants.
The third admission bonus, the “Happy Siren♪” pull-back car, will begin distribution in Japan on August 22 in limited quantities and will be available while supplies last.