Katie had been sucking on Tiff's breasts and thus in contact with her when the raygun had shot her. Thus, the raygun's energy flowed through her as well and they had both grown to 50 feet tall.
However, neither Katie nor Tiff seemed to notice that. Their bodies stretched through two floors and almost touched the rooftop, but Katie was still sucking vigorously on Tiff's breasts and Tiff was moaning. She moved her hands up Katie's body and pulled Katie's head away from her breast and then kissed her.
They started to remove their clothing, while still kissing. Neither noticed that the house was being destroyed as they went at it. The destruction went on as they rolled around and fondled each other and Katie even used a support beam as a makeshift dildo, but they didn't notice. In fact, they hardly noticed anything around them - they were totally fixated on themselves and having sex.
The next morning, Tiff and Katie woke up, nude and still 50 feet tall.
Looking around, they said simultaneously, "What the hell?"
Sun May 15 21:45:11 2005