"Monster" describes a good student played by Deng Yukai who has been teased by a group of three influential people in the class for a long time. One day, the four of them accidentally discovered a humanoid monster that eats people, which led to the topic of "bullying". This theme is also the theme that Jiu Ba Dao has always wanted to explore after being inspired by the Swedish movie "Evil" more than ten years ago. Originally, he wanted to shoot a "bullying pseudo-documentary" with a low cost of 15 million Taiwan dollars, and later turned it into a plot special effects film. Not only did he set up a stage at the Central Film Studio, but he also specially shot action scenes on the streets of Ximen Dingfeng. The production cost was increased to 100 million Taiwan dollars, and most of the cost was invested in special effects production. Jiu Ba Dao revealed that the original setting of the movie was to take a realistic and violent route, but he and the amateur actors could not grasp it, so he finally decided to be himself and go back to the black humor style.