Ultraman Wiki

Tetsuon (テツオン) is a monster introduced in Ultraman 80.

Subtitle: Juvenile Monster (少年怪獣 Shōnen Kaijū)


Ultraman 80

Tetsuon was originally a kid named Tetsuo who was a poor baseball player struggling to play the game and get along with his fellow members. After one of opposing baseball players accidentally knocked down a small UFO, the kids fought for ownership of the small disc when it deteriorated and revealed a small egg-like object that the kids fought for that two when Tetsuo accidentally caught the thing in his mouth and ate it. He suddenly felt tired when he left and decided to take a nap. When he woke up, he didn't realize that he had turned into a monster, Tetsuon, until his friend Taku showed him his reflection in a puddle and Tetsuon used his powers to bring back a lost ball.

To keep his monster friend safe, Taku and the other kids convinced UGM by telling them that the earlier UFO sighting was a hoax and then they convinced him to enter a costume contest and he won, with the prize being a camera set. The kids then decided to use that camera set to film Tetsuon fighting a kid named Nii in an Ultraman 80 costume with a city background and everything even though Tetsuon refuses to be the bad guy. The next day, the kids realized that Tetsuon was a pro when it came to school work so they convinced him to do others' school work in exchange for cake, but then UGM appeared and agreed to take Tetsuon for a regular check-up in exchange for letting him eat his cake soon afterwards.

The team then realized that the thing Tetsuon ate wasn't an egg at all, but a seed from a Space Plant. The thing is Tetsuo wanted to stay Tetsuon because he had these amazing powers much to the chagrin of his parents. However, negative consequences soon befell him when he was disqualified from the contest, taking back the prize, his studying meant nothing, and that his baseball skills have improved so much that the kids no longer wanted him on the team, leaving Tetsuon with no friends or family to hang out with. Feeling rejected, Tetsuon decided he wanted to return to normal, and Takeshi Yamato turned into Ultraman 80 and shrank into micro size and flew into his mouth and down into his stomach to fight the Space Plant in his stomach. He eventually defeated the monster and flew out of Tetsuon and Tetsuon finally reverted back to his normal child form. From then on, with encouragement from Takeshi, Tetsuo put in more effort into his life and eventually, his life improved physically and socially.


  • Suit actor: Tetsuo Yamamura
  • Voice actor: Kazue Takahashi
  • Tetsuon role are very similar to the monster Kanegon, as both started out as children before turning into a monster.
  • Tetsuon, when Ultraman Land was still around, was often paired with Kanegon, Booska, Pigmon, and even Ultraman Nice.


  • Height: 1.70 m
  • Weight: 100 kg
  • Origin: Tokyo Suburbs
Powers and Weapons
  • Intelligence: Testuon has a extremely high IQ level when swallowing the Space Plant seed.
  • Object Guiding: Unknown what other objects Testuon can guide to him, It is shown that he can guide baseballs to him at will.


Ultraman 80 Kaiju
Crescent | Gikogilar | Hoe | Zandrias | Alien Bam | Mechagiras | Abdolaars | Noiseler | Tabra | Gabishale | Jakki | Aruma | Zuruzla | Medan | Alien Vibros | Gora | Alien Gorgon | Saramandora | Zarudon | Myu | Devilon | Alien Ruria | Sawako Hoshi | Lavras | Daron | Gymaira | Gaus | Okorin Ball | Alien L85 Zuckal | Gamos | Underground Men | Queen Einus | Gomora II | Amoeza | Alien Fantas | Robo-Fo | Argon | Akuzone | Gera | Alien Argo | Val | Zakira | Cathy | Alien Zatan | Zatan Silver | Zora | Barrack Ship | Gazera | Angoras | Fire-Draco | Guwaganda | Baltan Warship | Alien Baltan V | Ghostdon | Tetsuon | Space Plant | Jihibikiran | Barebadon | Zurasuimar | Alien Galagala | King Galtan | Delusion Ultraseven | Alien Baltan VI | Marjin | Red King III | Glovusk | Idatenran | Plazma | Minazma | Margodon