Pixie Trixie is a klutzy pixie who messed with the pixie crystal. She appears in the pixie adventure inside a hidden area. Serena seems to be very disapproving of Trixie, especially when she tampers with the crystal. It's possible Trixie wanted to become the leader of the Woodsy Clan, but due to Trixie's apologetic behavior once she has the crystal, it's unlikely she had bad intentions.
"Oh no!" - Trixie when playing with the crystal
"You can't help me!" - Trixie in her home