Ben had fallen into a rather large funk. Not only had he lost his favorite alien form, Feedback, to Malware, but he had even been rendered with a feminine looking appearance he couldn’t even really fix due in part to Malware's glitching of the Omnitrix and his impatience in messing with it. This coupled with it extending even to his aliens, and also his hair constantly changing despite his attempts to keep it cut.

Gwen easily noticed her cousin’s dwindling mood, and felt a bit concerned. She decided that she had to do at least something, and that something was to get on his nerves. Using some of her magic after getting her cousin to visit her house, Ben was soon forced into a rather frilly lolita outfit, leaving him absolutely flabbergasted.

It also had the intended effect of getting him on Gwen’s case, pulling him out of his grumpiness and funk. Though then it turned around with him making a passing comment of ‘a boy pulling it off better than a girl’.

Put off by this, Gwen then decided to play off of his egomania. That the ‘Great Ben Tennyson’, ‘Hero of the Omnitrix’, was too afraid to be defeated by a little bit of girliness… challenging him by saying that he wouldn’t even be able to last a day hanging out with her dressed like he was.

And thus began what Grandpa Max jokingly declared ‘Girls Day Out: Starring Ben and Gwen’