Serena

Skye's Vespiquen (Skye's Beequeen, nicknamed Serena, is the third Pokemon obtained by Skye. Originally a small and frail Combee, it grew to become a powerful and bossy Vespiquen.

History
Skye caught Combee as a member of a group led by a Vespiquen in the Eterna Forest. She and John were chased off by this Vespiquen and her group of Combee, because they wanted their Combee back, but they got rid of them. Combee was very weak and only knew a limited number of attacks, but eventually it evolved into a Vespiquen and became very powerful.

Her personality isn't very good, however, as she thinks she's the boss and acts as the "queen bee" of Skye's Pokemon, always trying to boss them around. It even tries to boss Skye around as well, since it is bigger than her, but eventually learns that Skye is her master and tones down the bossy attitude.

Following her journies through Sinnoh, Skye dropped off Serena and the rest of her Pokemon at his house, starting with a clean slate for her travels through Unova.