Mask-A-Raid

Mask-A-Raid is a 1931 Fleischer Studios Talkartoon animated short film starring Betty Boop.

Synopsis
Betty Boop is queen of the Masquerade Ball. She get annoyed by the king of the ball. Bimbo does Italian scatting to confuse the king. Bimbo and the king pull on Betty's arms. Her skirt goes up, showing her underwear and her two garters. But a little creature pins the dress. Then, Betty flips a coin to see if the king or Bimbo wins her affections, but doesn't really work. So the king and bimbo fight with wooden swords. Bimbo loses and is taken away by a knight, but Bimbo soon realizes it is Betty and asks him to marry her.

Trivia
Mask-A-Raid is the first Betty Boop cartoon to show Betty as a human, which the character is best known being shown as.