Arnold's mother (ハジメのお母さん Hajime no Okāsan) is a character appearing in Pokémon: Indigo League.
Pokémon the Series: The Beginning
Arnold's mother was worried that her son did not come to her for few days. Ash and his friends decided to help her out and try to find out where Arnold had disappeared to. After Ash and his friends with the help of Officer Jenny tracked down the kids to a park in the middle of Hophophop Town, she showed up in the park and was reunited with her son.