Based on available sources, the character "Sunday-sensei" is documented solely through a 1991 Banpresto plush doll associated with the franchise *Hyokkori Hyoutanjima*. This doll measures 7 inches and features vibrant multicolored plush. No details concerning Sunday-sensei's role, background, personality, relationships, narrative arc, or specific appearances within any official *Hyokkori Hyoutanjima* media (including seasons, movies, OVAs, or spin-offs) are provided. Therefore, no additional information is available.