Jolly Roger Bay atmosphere

The Super Mario 64 course Jolly Roger Bay is initially home to a dark sky and a blanket of fog over the water. These atmospheric details vanish forever if the player collects the Power Star from Plunder in the Sunken Ship, as in future visits to the course, the sky is bright and the fog has disappeared.

Super Mario 64 and later 3D Super Mario games have several levels with different versions depending on the mission selected. However, the changes to Jolly Roger Bay do not follow this convention. Even if the Plunder in the Sunken Ship mission is replayed, the dark sky and fog will still be gone.

Courses in later games, such as Super Mario Sunshine and Super Mario Odyssey, have the time of day change after certain milestones. Perhaps Jolly Roger Bay was a prototypical analogue to those.

Why the sky changes and the fog clears as a result of clearing Plunder in the Sunken Ship specifically, though, is still unknown; making this mystery truly a strange detail.