He could just transform her into a dog and leave it that way until he figured out what to do. But who knew the side effects of leaving her like that? No he had to come up with a story.
He followed after her up to her room and knocked. He thought he heard lapping.
"What is it dork?" She said opening her door. Her face was wet, she'd clearly been drinking...and the light in the bathroom was on. Had she just had her face in the toilet?
"Look, Ally, there's something I need to tell you. I know you were just drinking out of the toilet. Owwww!" She slapped him.
"I was not!" She exclaimed angrily.
"Ally look. This is important. You've been cursed by a witch. Any time you hear....well a phrase...you start turning into a dog."
Ally looked at him for a second then burst out laughing. "Yeah, right. Magic isn't real do you expec-bllllleeeeeeechhh!" Her tongue suddenly expanded in her mouth as he told her good girl.
"Barbie doll." He said immediately. "You can't remember what just happened can you? That's because you get really dumb when someone says it. Like dog dumb. You've got to stay away from situations where someone might say..." He wrote down the phrase.