Susan and Mary purposely turn themselves into babies while the parents are out, and Johnny has to keep them safe from the irresponsible babysitter Gil.
This episode contains examples of:
- Abusive Parent: At the beginning, Hugh threatens to punish Johnny (instead of Susan and Mary) if any more transformation experiments (not matter what) in the Test house.
- Baby Morph Episode: For both Susan and Mary, as part of their scheme to have Gil take care of them.
- The Diaper Change: Inevitably happens, and Gil proves to be extremely wimpy about it.
