Like all Wafflesworths, Yvette was once a human, but was transformed into another form. In her case, she was learning to cook an experimental recipe, but accidentally used too much melange and was transformed into a porpoise.
Her usual garb consists of an apron.
Yvette is a loving mother and thinks only the best of her two sons. A traditional housewife, she takes care of the home while her husband works. She also has a tendency to assume two people are in a relationship, even when they aren't, or even when they "aren't". While most people just explain this as motherly misunderstanding, a few believe that Yvette sees more than is shown to her.