Crossing the Line (Shellback Ceremony)
Cross the equator by ship for the first time and you're a slimy Pollywog — until King Neptune's court makes you a Shellback.
How it actually works
Sailors who have crossed the equator aboard ship are Shellbacks; those who haven't are Pollywogs (or "slimy Wogs"). The night before the crossing is Wog Day. On crossing, the Pollywogs are summoned before King Neptune's court — King Neptune, Davy Jones, Her Highness Amphitrite, all played by the most senior Shellbacks aboard — and put through a run of initiation trials before earning a certificate and their new status. Rarer tiers exist: a Golden Shellback crosses the equator at the 180th meridian; the Emerald (or Diamond) Shellback crosses it at the prime meridian. The Coast Guard and embarked Marines run the tradition too.
It gets romanticized as harmless saltwater fun, and the honest history is more complicated than that. For centuries the ceremony was genuinely brutal — Pollywogs beaten with boards and wet firehose, dragged through the sea, with deaths on the record — and even the modern version has repeatedly slid into hazing that the Navy has had to formally rein in. It's a cherished, centuries-old rite of passage AND a tradition with a real accountability history. Both of those are true, and an honest telling keeps both.
Western seafaring initiation, centuries old; formalized in U.S. Navy tradition