so sensei either crossed into another dimension or was surrounded by phantom fables.
see pg33. everyone is in on it, including shizuko (see her eyes and the way everyone was looking in the direction of sensei).
creepy. thanks wakamo you're getting a thousand kisses for escorting sensei
camera pans to Akira's POV, revealing sensei's face. A piece of paper with a doodle of a face on it appears to be taped to his forehead, covering his whole, actual face.
pretty sure all of them are schizo to varying degrees. I mean we have kakizaki who, as one comment said on that chapter, had a delusion involving isekai, gangrape and NTR... all from simply hugging sou.