In the early days of Dragon Ball, he was an attractive character whose personality changed when he sneezed.
As the Saiyan arc begins

Among them, there are two most famous stories.

(gpt translation)
As for the reason,
Some say that this is because there were protests from organizations supporting mentally ill patients due to the setting of ‘dual personality’.
Another theory is,
Originally, (the character) was planned to appear gradually, but during the series, a serial girl kidnapping and murder case occurred, and the production team refrained from doing so because the media was talking about suspicions that the criminal had a double personality, such as using a false name and issuing a statement of the crime.
It was just a baseless urban legend that people complained about discrimination against multiple personalities and then disappeared.

But it doesn’t make sense that Toriyama forgot lunch.

“”Damn, where did you go?
During the Freezer War, there was a special project to draw a picture of a character who had not appeared in Jump for a long time, and a lunch was made there.

Number 17, who heard the voice, says, “It’s been a while since I heard that voice,” but this is wrong.
In the original work, Son Goku and No. 17 had never met. Therefore, the line “It’s been a while since I heard that voice” is a very strange part.
There is a story about this in the first edition of the Dragon Ball encyclopedia that came out later.
gpt interpretation
Mr. Lunch went after Cheonjinban.
And since I was training with Chaozu on the Tianjin Peninsula and wandering around here and there, we never got to see each other.
They’re probably perfectly aligned.
Android No. 17, who appeared near the final episode, was actually Mr. Lunch during the rough sketch stage.
He revealed that in fact, that scene was originally planned to feature Lunch, not No. 17.
Therefore, it can be said that Toriyama forgot lunch is incorrect.
Then, this year, the reason for its disappearance was finally revealed.

相は長らく不明であったが、2025、の小山がラジオ
でその理由を明かした。それによれば、「Private worldのためしばらく日本を離れるので、ランチさんをさないでくださいって鳥山先生に直接お願いした」とのこと。
事、小山は1980 1 year 1 business しており、ランチ以外の役も降板している。小山は前述の通りアラレちゃんの優でもあり、鳥山と親交も㷱かったため、このようなお願いが可能だったのだろう。
*5
ゆう坊&マシリトのKoso Koso放送局March 29日放送分
gpt interpretation
The truth was not revealed for a long time, but in 2025, Koyama, the voice actor in charge, revealed the reason on a radio broadcast.
According to him, “I was leaving Japan for a while to study abroad, so I directly asked Toriyama-sensei, ‘Please do not feature Mr. Lunch.’”
In fact, Koyama took a year off in 1980 and stepped down from roles other than lunch.
As mentioned earlier, Koyama was the voice actor in charge of ‘Arare-chan’ and had a close relationship with Toriyama, so it can be seen that such a request was possible.
Mami Koyama, the voice actress in charge of Lunch, revealed the reason on a radio broadcast this year.
In other words, since he had to go abroad to study for about a year, he couldn’t take over the lunch job, so he asked Toriyama not to make him appear.
Ultimately, because of this, Lunch was completely excluded from appearing and did not appear in the work.