Lumineon appeared in a cave which was nearby the lake the Pokémon Summer Academy used for their second activity. Its fins' blue light hypnotized Ash's Pikachu, Dawn's Piplup and Angie's Shinx with the latter going to the cave where Lumineon was. The heroes went to the cave to retrieve Shinx and saw Lumineon as well. After the battle between Jessie and Conway, it disappeared from the cave. Brock concluded that Lumineon came to this cave to eat from seawood that grew there. The heroes and Angie decided to hold their presentation about Lumineon.
None of Lumineon's moves are known.