1. Originally, in the One Piece manga, when Hililuk is introduced, he gives an injection to a sick man, but the man gets a seizure. The man's wife gets shot by Hililuk for attempting to call the police, and their daughter is traumatized. Later, in the anime, the man turns into a frog upon said injection.
2. Each character in Komi Can't Communicate's names are based off the words that are their most defining trait.
3. When drawing Dio, Hirohiko Araki couldn't find a weakness in his character that would result in a way to defeat him.