Director Jeong-won Shin said his film adopted a typical Hollywood B movie monster narrative to tackle environmental issues, particularly the serious destruction inflicted on Korea's ecology. He said Korea had never had a film dealing with real-life killer creatures like Alligator and Anaconda and was "intrigued by the idea of a familiar animal attacking and killing humans and wanted to create something out of this unexpectedness. But most of all, I wanted something funny and unique."
The title is pronounced "chow", which means "trap" in Chungcheong dialect.
After filming in Seoul, the production crew and the main actors flew to the United States to shoot special effects scenes. The shooting lasted for 40 days in San Francisco. Misunderstandings in interpreting the nuance of a scene or dialogue sometimes arose between the U.S. special effects team and Korean actors due to different cultural backgrounds, but Uhm said, "after the shooting was over, we formed a strong team spirit, as if we battled together in a war."
In the UK Cuts were made to remove sight of unsimulated cruelty to animals (a boar being chased and attacked by dogs; a live deer strung up and struggling on a frame; a live eel being cooked). These scenes of animal cruelty appear to be in other releases of Chaw.