Girl Trouble

Girl Trouble is the 25th episode of Ben 10: Ultimate Alien, and its the fifth episode of the second season.

Plot
The group go to Gwen's house in order to find a solution to stop Computron's minions from Dimension 12. When they go inside her room, they already find another girl on her bed. She introduces herself as Sunny, a related member of the Tennyson family, as a cousin of Ben and Gwen.

Gwen tries to persuade her mother to get rid of Sunny, but she explains that Sunny is staying over the summer because her parents want her to be around a good influence like Gwen. Sunny tries to flirt with Kevin, and is forced to go with them to stop an invasion of Dimension 12 robots, and she annoys all of them during the car ride. When they arrive at the location the robots are appearing, they fight them, with Ben becoming Four Arms. Sunny sees the commotion happening, and gets out of the car to see. She then reveals her stronger Anodite powers, and destroys the rest of the robots, shocking everyone.

Gwen's mother is informed of Sunny's Anodite powers, and thinks of whether she should stay or not, considering her dislike for certain Anodites. Suddenly, they get a visitor, and it is revealed to be Sunny's boyfriend Antonio, who she always kept talking about, but Antonio is really a giant, caveman-like alien with little intelligence. Sunny decides to run away with Antonio, and before they could go over them, the group is informed of another attack of the Dimension 12 robots. The robots plan to use a particle accelerator on a small canister bomb to make its energy levels stronger in order to blow up the whole planet. Ben transforms into Lodestar and they start fighting the robots again, before Sunny and Antonio join the fight. Kevin shuts down the particle accelerator by smashing its control device, and when they try to get Sunny to go back home, Sunny refuses to and sheds her human skin, revealing her Anodite form.

When Gwen threatens to tell Sunny's parents about her misbehaving, a fight ensues. Gwen fights Sunny, Ben fights Antonio as Humongousaur, and Kevin is in charge of making sure the upgraded canister bomb does not blow up and kill them all. Sunny overpowers Gwen, and Antonio's strength is too much for Ben, so he becomes Ultimate Humongousaur and quickly gains the upper hand. He tricks Antonio into picking up a lightpost, electrocuting him and knocking them out. Kevin disarms the bomb by pulling its cord. Before Sunny could finish off Gwen, Grandma Verdona arrives and overpowers Sunny, trapping her in her own shield. She also takes the unconscious Antonio, and says that their parents are going to have to sort out everything. Verdona says good-bye and offers Gwen another chance to go to Anodyne with her to practice her powers, but Gwen turns the offer down again. Verdona leaves with Sunny and Antonio, and the group goes to clean up the robots' mess.

Characters

 * Gwen Tennyson (main character of this episode)
 * Ben Tennyson
 * Kevin Levin
 * Verdona Tennyson (first re-appearance)
 * Lili Tennyson

Villains

 * Dimension 12 Robots
 * Antonio
 * Sunny

Aliens Used

 * Four Arms
 * Lodestar
 * Humungousaur
 * Ultimate Humungousaur

Errors

 * In one scene, the black 10 emblem on Ben's jacket is white and the 10 is in black text. (same like in episode Duped)
 * If you look closely when Antonio is throwing Humungousuar, Humungousaur's Toes are the same color as his scales.
 * When Ben transforms into Lodestar his voice had changed
 * When Kevin is trying to stop the bomb from becoming more powerful, the on-off switch look alikes are all set to the off position. As soon as the camera changes to a few frames before Kevin smashes the machine, one switch is set to on.
 * Lodestars eyes are way bigger than usual.

Trivia

 * There is a running gag in this episode that the tone that most of the characters speak in is in a bratty way.
 * In this episode Lodestar's voice sounds like the battle droids in the Star Wars saga.
 * This is the second time Gwen fights one of her cousins. First being in Absolute Power: Part 1 against Ben.
 * When Ben kicked Antonio into the goalpost, he kicked a goal in general.
 * This episode reveals that Ben and Gwen have another set of Aunts and Uncles.
 * It seems that the robots from Dimension 12 have now become enemies of Ben and his friends, since they were featured in this episode.
 * This is the third time an Anodite is seen in the series. The first one was Gwen, and the second was Verdona.
 * Ben has now used all of his original ultimate forms in this season, but Ultimate Wildmutt has yet to make an appearance.