Chapter 23

Confusion and Slaughter (混乱と殺戮, Konran to Satsuriku) is the 23rd chapter of the Parasyte manga series, written and illustrated by Hitoshi Iwaaki.

Overview
''Yuko is able to escape after defending herself and throwing hydrochloric acid on Hideo. However, this causes Hideo to start slaughtering people around the school, unable to stop himself. Shinichi begins heading towards him in hopes of saving Satomi Murano and stopping him from killing more people. While searching, Shinichi comes across a hallway with numerous mutilated bodies on the floor.''

Summary
Shinichi yells at Migi to tell him where Hideo is, then realizes Migi can't talk with his teacher and classmates all watching. He leaves the class.

Hideo tells Yuko not to move because it'll hurt more if she does. She manages to block his first attack with a metal canvas and catches a bottle of chemicals she'd picked up earlier, throwing it to Hideo who instinctively attacks it. It splashes all over him while Yuko crawls out the window, leaping into a tree and falling to the ground as one of Hideo's segments peer out from the window. The students nearby check up on her and call an ambulance.

In the room, Hideo realizes that the chemical was sulfuric acid, and in changing shape had mixed it into his body.

Two of the students watching over Yuko go to check what had happened upstairs.

Migi directs Shinichi to Hideo, but states that his consciousness is fractured and something dramatic must have happened to him.

In the school hallway, a teacher crosses paths with the two students and goes to look in the art room.

Hideo struggles to remorph himself to look human, but due to the dead cells in him his consciousness is split up nad unable to recombine, with parts of him stuck in attack mode. The two students and teacher come up to him and he kills them. Migi lets Shinichi know.

More staff come across the carnage and go to evacuate the school and call the police, one of them barely coherent in his panic.

Because of Hideo's damage, Migi can't pinpoint his signal, eventually figuring out that moved to the same building as Shinichi's class. Migi tells him that they can't fight with the students in the way and should evacuate as well. Yamamoto comes up and smacks Shinichi for not following the class, telling him to leave the building.

Kamijo and Nagai as well as a few other students joke about last time's Killer A and this being Killer B. Shinichi spots Satomi in the crowd, but is unable to stop to meet her. The frantic teacher who first witnessed the carnage shrieks at them to hurry. Panicked, he decides to take his class another way out. Outside, the students learn they have to leave their stuff behind and go home, with the staff being insistent and even willing to pay for their train rides if needed. They then realize that class 2-3, Satomi's class, hasn't showed up yet.

Shinichi furtively hops back into the school through a window and declares his choice to fight now that everyone's evacuated. The missing class then shows up, screaming and running out. Migi muses that Hideo is reflexively attacking anything that moves, and tries to tell Shinichi that he's on the second floor with ten others. Shinichi realizes that Satomi is still missing and remembers the last time he spoke, yelling at her to shut up. He runs upstairs and comes across a scene of slaughter.

Shinichi freaks out and Migi tells at him to calm down while his heart feels like it's about to explode. He has flashbacks to Satomi telling him he's changed, his scar, his mother and father, and him deciding to change his hairstyle because half of him feels heavy. Upon recalling his father's words that he's made of iron, he calms down almost instantaneously. He then walks through the carnage and spots a head that resembles Satomi. He turns it over, and, discovering that it's not her, repeats her words from the last chapter that he thought she was someone else. He decides that he'll kill Hideo once he finds Satomi.