Hideo Shimada's Rampage

Hideo Shimada's Rampage is the event that caused the media and greater public to become aware of the existence of parasites. When Hideo attempted to kill Yuko Tachikawa for confronting him, she retaliated with a bottle of concentrated chemicals that damaged his parasite cells. This caused him to be unable to return his head to normal and he involuntarily attacked everything that moved around him, causing a total of seventeen deaths. He was eventually killed by Shinichi and Migi.

Plot
The event begins when Yuko confronted Hideo in school and defends herself from his attack with a jar of caustic liquid (paint thinner or sulfuric acid). The liquid damages his parasite cells greatly, causing him to lose his morphing capabilities and become stuck on attack mode. Yuko barely avoids becoming the first casualty by jumping out a second-story window. As Hideo moves through the school, he uncontrollably slashes out at anything that moves.

Shinichi and Migi are the first to realize he is on the attack, but are unable to do anything while they're still in school.

As the first witness to Hideo's initial victims, Satomi Murano's teacher raises the alert in a panic, prompting the school to gradually evacuate. Unable to calm himself while waiting for the crowd to filter out the main exits, he then heads off to collect his class and find another exit.

Later, outside the school, people begin to roll call and realize Satomi's class is still missing. Shinichi then heads back inside and stumbles on the majority of the murdered class, including her now-deceased teacher. After suffering a quick panic attack, he calmly steps through the gory remains and finds a decapitated head with a hairstyle resembling Satomi's. He turns it over, realizes it's not her, and focuses on his hearing. He hears Hideo's growling and three other survivors.

Shinichi quickly finds the three survivors, including Satomi. Although he attempts to herd them out the way he came, two of them become horrified that he walked through the bodies of their classmates and flee from him, immediately being killed by Hideo. Because Satomi is unable to walk from the stress and Hideo is so close, Shinichi picks her up and leaps out a window, landing unharmed despite it being several stories up. He then gives her to the medics on scene and decides that he has to help stop Hideo.

Trivia

 * Although some students joked about this event being the Attack of Killer B (in reference to A's attack, it has no relation with the parasite B.