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Arnold is reunited with his mother.
Arnold's mother (Japanese: ハジメの母親 Hajime's mother) is a character of the day from Hypno's Naptime. Her Japanese voice actor is 愛河里花子 Rikako Aikawa. Her English voice actor is currently unknown.
Arnold's mother was shown early in the episode and had mistaken Ash for her son, Arnold. She revealed that Arnold, like other children, had disappeared three days before Ash and his friends had arrived to HopHopHop Town. Unbeknownst to her, this was due to a Hypno's sleep waves, which were being used by socialites to treat Insomnia and as a novelty. The sleep waves had unintentionally effected a larger area than desired, and had brainwashed several children into believing they were various Pokémon. They all had gathered in the park, imitating the Pokémon they believed themselves to be, until Ash and Co, upon discovering their location and the cause of their strange behavior, brought Hypno to the children. Hypno promptly undid the brainwashed behavior and the children returned to normal and were reunited with their parents.
By the end of the episode, Drowzee used dream waves to wake up all of the children in the park, where Arnold's mother and Arnold were reunited.