Mrs. Widdershins is the wife of Captain Widdershins and mother to Fiona and Fernald. Not much is known about her but she was most likely on the fire-fighting side. She was one of the original crew members of the Queequeg. Although Widdershins claims she died in a manatee accident, Lemony Snicket later hints that Fiona was correct in her disbelief of this explanation.
- "The submarine Q and its crew of two" originally referred to her and her husband.
- There is a theory that Mrs. Widdershins and Miranda Caliban are the same, meaning Friday Caliban is also her daughter.
- Fernald, Fiona and Friday are all names beginning with F, which could support this theory.
- Another fact supporting this theory is that most siblings in the series come in groups of three, and even on the rare occasions that only two siblings are known of, the existence of a third sibling is usually hinted at (such as the White-Faced Women).
- The Grim Grotto (mentioned)