Flannery first appeared in Poetry Commotion!.
In the anime, Ash and his company see a Slugma running from a girl with blazing red-hair. They find out that she is none other than the new Lavaridge Town Gym Leader, Flannery, who had been training with her Slugma. They are secretly helped by fake workers, who are actually Jessie and James of Team Rocket, an old man and a judge who is actually Flannery's grandfather. Flannery's grandfather saves the day when Team Rocket attempt to steal Flannery's Torkoal. In the resulting Team Rocket battle, one of her Slugma evolves into a Magcargo.
In Going, Going, Yawn, Ash has his Lavaridge Gym battle. In the battle, he uses his Corphish, Pikachu and Treecko. Despite Corphish being hit by a Yawn from Flannery's Slugma, Ash manages to defeat Torkoal and win the Heat Badge.