Bowser's Sister

Bowser's Sister is one of Bowser's family members. She is only mentioned in the song Ignorance is Bliss. Bowser mentions that Princess Peach reminds him of her sister.

Since she only has one mention, little is known about her, besides the following facts:
 * She is younger than Bowser ("You remind me of my kid sister").
 * She enjoys reading ("She read so much, she got a blister").
 * Bowser thinks lowly of her ("What a shnook!").

Nothing else is known about her, not even her name, though anything mentioned in the lyrics of Ignorance is Bliss is not considered very canonical. Note that since she is the sister of Bowser, her last name most obviously be "Koopa".