Rex the Runt (1998)

Wendy has been nominated for the Nobel Prize for Science for the truth serum she's been working on in the spare room. The dress code on the invitation to the award ceremony says Scientific yet sexy: no white coats and Wendy decides to get her hair done. While she's out Bob and Rex consume the serum, which makes for a revealing afternoon particularly when Wendy returns and they tell her she's bald.