Casio F-91WS-8 'Jelly', probably the most interesting F-91W I've seen : r/ casio
So i heard this sub likes skeleton watches.... The Seiko ref. Prclas666. A well known homage of Casio f91-w. Also known as the “Ghost alpinist”. Legend says the time is only visible
Casio F-91W: The Best Wristwatch in the World? - Wristwatch Review UK