o-Man is a standard NPC that can be found in the Mall's Flute Room. He is sitting on a sofa in a room which has a flute lying on the floor that gives the Flute effect, alongside a strange poster on the wall. His appearance is like a purple "O" or "θ" with a single red eye in the center, with two pink legs and light purple shoes, producing music with notes coming out around him. He is similar to the character known as e-Man in the previous room that has a Toriningen at the counter.
If the player uses the Cat effect, he will act like he's angry or uncomfortable, like certain other characters, such as e-Man and the Train Passengers. The player can also stop the music with the Stoplight or kill him by using the Knife effect. Afterwards she can sit on his sofa and the BGM of the room will stop entirely.
- The parallax background in the Graffiti World somewhat resembles o-Man and e-Man, indicating a recurring significance of the characters as these two locations connect to each other.