History YMMV / Mouse2021

* HilariousInHindsight: This isn't the first time Hyun Bong-sik appeared in a show about serial killers. He played Hee-joong, one of the killers' victims, in ''Series/StrangersFromHell'', and here he plays Ho-nam, one of the police tracking down the killers.

* CompleteMonster: [[MadDoctor Dr.]] [[SerialKiller Han Seo-joon]] pretends to be a normal doctor but is secretly the serial killer known as the Head Hunter. He beheads his victims then experiments on their brains. He kills at least twenty people and beats a young boy almost to death before finally being caught. Later, after years in prison, he still shows no remorse for his crimes and gleefully continues to experiment on animals. He's briefly brought out of prison to transplant part of his son Yo-han's brain into Ba-reum's. When his wife confronts him he reveals he harvested their son's brain ''while Yo-han was still alive'', and [[PsychoSmirk smirks]] at her reaction. He remains unrepentant to the very end. Just before his death he boasts of his plans to escape and continue killing people.

** Bong-yi. She was kidnapped and raped as a child, her grandmother is murdered, and her friend is turning into a psychopath and almost kills her. Then she learns her friend [[spoiler: was a serial killer all along and is her grandmother's murderer]].

* WhatAnIdiot: Daniel Lee arranges to meet someone alone. In a closed-up amusement park. Late at night. ''When a serial killer is on the loose''. Unsurprisingly he gets killed. [[spoiler: Then subverted when it turns out he's still alive and staged his apparent death.]]

* CompleteMonster: [[MadDoctor Dr.]] [[SerialKiller Han Seo-joon]] pretends to be a normal doctor but is secretly the serial killer known as the Head Hunter. He beheads his victims then experiments on their brains. He kills at least twenty people and beats a young boy almost to death before finally being caught. Later, after years in prison, he still shows no remorse for his crimes and gleefully continues to experiment on animals. He's briefly brought out of prison to transplant part of his son Yo-han's brain into Ba-reum's. When his wife confronts him he reveals he harvested their son's brain ''while Yo-han was still alive'', and [[PsychoSmirk smirks]] at her reaction. He remains unrepentant to the very end. Right up to the minute of his death he plans to escape and continue killing people.

* CompleteMonster: [[MadDoctor Dr.]] [[SerialKiller Han Seo-joon]] pretends to be a normal doctor but is secretly the serial killer known as the Head Hunter. He beheads his victims then experiments on their brains. He kills at least twenty people and beats a young boy almost to death before finally being caught. Later, after years in prison, he still shows no remorse for his crimes and gleefully continues to experiment on animals. He's briefly brought out of prison to transplant part of his son Yo-han's brain into Ba-reum's. When his wife confronts him he reveals he harvested their son's brain ''while Yo-han was still alive'', and [[PsychoSmirk smirks]] at her reaction.

* TheWoobie: It would be easier to list everyone who isn't one.

** Ba-reum becomes this after his LaserGuidedAmnesia. He learns part of his brain was replaced with Yo-han's and assumes he's gained Yo-han's memories of committing murder. But soon he discovers the truth: [[spoiler: ''he'' is the killer, not Yo-han, and he's regained his original memories]].

** Yo-han. He's falsely accused of being a serial killer and then killed by his own father.

* TheWoobie:

* TheWoobie: Bong-yi. She was kidnapped and raped as a child, her grandmother is murdered, and her friend is turning into a psychopath and almost kills her.

* WhatAnIdiot: Daniel Lee arranges to meet Yo-han alone. In a closed-up amusement park. Late at night. ''When a serial killer is on the loose''. Unsurprisingly he gets killed. [[spoiler: Then subverted when it turns out he's still alive and staged his apparent death.]]

* WhatAnIdiot: Daniel Lee arranges to meet Yo-han alone. In a closed-up amusement park. Late at night. ''When a serial killer is on the loose''. Unsurprisingly he gets killed.