Penelope is Alfalfa Switzer's maternal aunt from San Sebastian. She's not particularly welcomed by Alfalfa's father. She's a sculptress and later a novelist. Her fiction based on her nephew convinces Alfalfa and the gang that she's planning a murder; the confusion causes a bit of an incident. She is probably Cousin Wilbur's mother, but that's unconfirmed.
Aunt Penelope was played by Marie Blake, later known as Blossom Rock of "The Addams Family."