Toriyama drew several short omake manga included in the Dr. Slump tankōban volumes that supposedly depict the actual events of how he came up with the characters, although, as they are often humorous, the level of truthfulness to them is uncertain.
The character Nikochan, an alien species with their buttocks on their heads, was hastily created after Toriyama was pressed for time having played too many video games and was initially rejected as "filth", with him given another night to re-work it [REF].