The benefits of being invisible are starting to sink in for Frank now that he has enjoyed his mom and sister. It was only natural that his mind wandered to his babysitter. More
Noticing how mom and sis got off on being plundered by an invisible man, Frank wonders how hot his babysitter will get. Especially if she mistakes him as a ghost like his sister did. All he can think about is how big her breasts are as he heads to her apartment. How shapely her back side is as they spill out of those tiny shorts she always wears.
He is relieved when he sees none of the men looking for him are outside her building. He needs plenty of time to do the naughty things he has in mind.