Wet-Dry World Girl

The Wet-Dry World Girl is an NPC located in Wet-Dry World and allegedly in some instances the Internal Garden located on the Fourth Floor in some personalized copies of Super Mario 64. The NPC has a model unlike any other, usually resembling a ghostly young girl with brown hair, white eyes and a red dress.

Behavior
The Wet-Dry World Girl is most commonly seen idly in the downtown section of Wet-Dry World, though some people have reported her appearing in the Internal Garden as well. When approached, she reportedly stares at Mario, even if he is directly behind her. Her dialogue differs from copy to copy, though it usually portrays her as a kind person who looks up to Mario and mentions an event called "the flood."

In the Internal Garden, she is usually seen standing near the pond, though there have been multiple reports of her being located elsewhere in the garden. When talked to, she usually remarks on Mario doing a good job, rarely giving him lives or even a star, which would count as a castle secret star. Upon talking to her a second time, she usually remarks about how the water reminds her of home.

Theorizing
Some have theorized that "the flood" mentioned by the NPC may be referring to Wet-Dry World's skybox, as it appears to resemble a flooded town. This may explain her sometimes ghostly appearance, as she may have drowned within the submerged town.