Midnight Horror School (Japanese: 真夜中のホラースクール) is a Japanese computer-generated anime series created by Naomi Iwata (who also created Pecola and Gregory Horror Show), and produced by Milky Cartoon. The series began in October 2003 until March 2004, and aired on the satellite network Animax
- Ampoo (Voiced By Chiyako Shibahara): A quiet plug boy. He always makes a fuss. His color is purple.
- Borocca (Voiced By Junji Majima): A plain boy with his head shaped like an umbrella. When he gets excited, his umbrella head opens and closes. When he cries, it rains, which in this case he can make the school become a downpour. His color is aquamarine.
- Chaps (Voiced by Mochizuki Hisayo): A half-melted candy girl. When she tries to do too many things at once, she melts. Her color is light green.
- Docky (Voiced by Mayumi Tanaka (Season 1) and Takeshi Kusao (Season 2): A loner that wears a firefighter hat with the number 13 on his head. Girls look at him with a curious eye. His color is red.
- Enton (Voiced by Tarusuke Shingaki): A boy with his head shaped like a chimney. He is always upset. When he gets excited, he puffs smoke, which annoys everyone. His color is brown.
- Fonton: A fountain pen boy who often leaks ink. He is a maniacal note-talker. His color is light yellow.
Genie (Voiced by Ryuzou Ishino): A boy who loves to study. He is smart, his head is shaped like a book reader and he wears glasses. His color is green.
- Hikky (Voiced by Hiromi Otsuda): A two-sided pencil stub boy. He's one of the most common protagonists in the series. He really loves to draw. Hikky is friends with everyone, mainly with Liddy, Spimon and Piranin. He has 2 colors: Red and dark blue. The two different colors represent two different personalities.
- Inky: A blue ink bottle boy. He watches things from afar. His head changes color at every emotion. His color is baby blue.
- Juno (Voiced by Tomoe Hanba): A flower pot girl who always carries around a man-eating plant on her head. She also has a big sister. When she gets angry or serious, the man-eating plant on her head gets violent. She has 2 colors: Salmon pink and dark green.
- Kabo (Voiced By Tomoko Kawakami): A pumpkin boy. He is the son of a pumpkin king and is very likable. His color is orange.
- Liddy (Voiced by Tomoko Kawakami): A keyboard instrument girl who is strong-minded, outgoing and popular. Just like Hikky, she is one of the most common protagonists in the series. She plays the organ and is very good at music. Liddy is one of the two girls that Hikky talks to more (the other girl being Juno). Yumyum has a crush on her. She has 2 colors: Pink and red.
- Magnero (Voiced by Setsuji Satoh): A magnet boy who always has a scrap metal stuck to him. He likes to build machines and collect magnetite sand. His color is gray.
- Noisy (Voiced by Tomoe Hanba): A microphone girl. She also has a show called "Midnight Eye" where she reports on the latest gossip. Her color is pale purple.
- Ompoo (Voiced by Sakiko Tamagawa): A music note girl. She loves music and is very good at singing. She's not as scary as everyone else. Her color is aquamarine.
- Piranin: A half-fish boy who is always ill. Just like Hikky and Liddy, he's one of the most common protagonists in the series. He enjoys swimming around in the school fountain. He usually stays in the back, away from others. His color is olive green.
- Quicky (Voiced By Hiroko Emori (Season 1) and Takashi Kusao (Season 2) : A clock boy. He is always worried about time. Like Hikky, Quicky has a friendly relationship with Docky. He has 2 colors: tan and orange.
- Rosso: A shy fire hydrant boy. He loves to water Juno's plant, but gets nervous about watering things around anyone else. Yumyum, Tubee, and Usop bully him a lot. He shoots out a lot of water every time he cries. His color is red.
- Spimon: A monkey boy with speakers for ears. Just like Hikky, Liddy, and Piranin, he's one of the most common protagonists in the series. He is always broadcasting something very quietly, but he doesn't like to do it loudly because it hurts his ears, and sometimes knocks him unconscious. Noisy likes to play gossip through his speakers. He has 2 colors: Light green and yellow.
- Tubee (Voiced By Chiyako Shibahara): A paint tube boy. Tubee is the bully of the Yellow Lizard Class, making him one of the main antagonists in the series. He is a troublemaker who always drips paint everywhere. He tries to do things to get Hikky angry. When ever Borocca starts to cry, Tubbe does things to make sure Borocca doesn't cry. Tubee has a crush on Noisy. He has 2 colors: White and purple.
- Usop: A spray paint can boy. Like Tubee, he's one of the main antagonists in the series. Usop is the bully of the Blue Spider Class. He is a liar and has a strong dislike for most people. His color is beige.
Vincent: A quiet bottle-head boy. Like Inky, his head is a bottle. But unlike Inky, his head is full of jellybeans instead of ink; he likes to read, and he doesn't have a mouth. He also enjoys daydreaming. His color is yellow.
- Watt: A light bulb boy. His light burns out when given too strong an electrical charge. Watt has a friendly relationship with Ampoo. He has 2 colors: White and blue.
- Mr. X: A transfer student with a paper bag over their head, which they never take off. They don't talk much. Their color is tan.
- Yumyum: A mischievous rotten banana boy with his head being shaped like a banana. Yumyum is the bully of the Pink Toad Class. Just like Tubee and Usop, he's one of the main antagonists in the series. He's the leader of the 3 bullies. The other students hate him when he starts to smell bad. He can summon and control flies. He tries to make sure that the banana inside his head (his insides) doesn't come off him because if it does, Johnny Crow will take the banana away from him (resulting in Yumyum, Tubee and Usop to go after Johnny Crow). Yumyum has a crush on Liddy, His color is yellow.
- Zobie: A zombie boy. He also has a coffin, which he can found resting in during break time. His color is blue