Lieutenant Major Goose (also known as Mr. Goose) is the main antagonist in Hey Arnold episode, New Teacher and cameo appearance in the episode Veterans Day.
After Mr. Simmons quits being a permanent teacher because of his class's discipline problem, Principal Wartz hires Mr. Goose as a replacement.
When Mr. Goose sees the pencil drop by Curly, trying to play a prank, Mr. Goose demands him to stand in the corner. Mr. Goose also sends Helga and Harold to the corner for laughter. Stinky is then sent to the corner just because of symmetry (When Curly, Helga and Harold stood up, there where empty seats in an L-shape. When Stinky moved it was a complete square).
The kids realize that Mr. Simmons was a much better, kinder teacher, and plot against Mr. Goose to get Mr. Simmons back. The next day all of the kids bombard Mr. Goose with random questions, which Mr. Goose becomes irritated and the kids starts laughing at him. Principal Wartz comes by and Mr. Goose decided to quit teaching and running away screaming. Mr. Simmons walks into the class and becomes the permanent teacher again and he declares that schedules are for Lieutenant Majors.
Mr. Goose has a cameo in the episode "Veterans Day". He served in the U.S. Army as a drill sergeant in the Vietnam War.