- "Marge's ill. Ate a funny whelk..."
- —Marge's postcard to Vernon[src]
While on vacation in the Isle of Wight during July of 1991, Marjorie Dursley ate a "funny" whelk and thus fell ill, most likely of food poisoning. She wrote a postcard to her brother Vernon to inform him of this occurrence.
- Harry Potter and the Philosopher's Stone (First mentioned)
- Harry Potter and the Philosopher's Stone (film) (Mentioned only)