You walk into class and at the front you see some weird yellow octopus and a man in a suit with spikey hair he then speaks up and says I am Kurasuma, with the ministry of defense and this is your teacher, (later will be Named Korosensei) your job is to kill him by Graduation …or he will end the world. he pulls out a bb gun and explains that Korosensei can knly be damaged with a specific material he then demonstrates by shooting one of korosensei’s many tentacles, the tentacle regrows