The "Phantom Girl" is an Easter Egg character in Yandere Simulator. She can only be seen if the player takes photos in the female bathroom on the 3rd floor. No matter what angle Yandere-chan takes the picture from, the Phantom Girl will always be facing towards her.
"The first tragedy.
A flower plucked far too soon.
She can not yet rest."
The Phantom Girl wears a torn version of the default seifuku uniform with torn socks and only one shoe. Her hair is shoulder length and brown. She wears a white Japanese funeral headband. Her skin is light blue, however her face is blackened out except for one glowing yellow eye. She is surrounded by two neon blue flames.
An early post in the YandereDev's blog titled "Halloween and DLC" featured some ideas for the game, one of which included the Phantom Girl. In this post, YandereDev described a scenario for some possible DLC content that includes the Phantom Girl.
"Yandere-chan’s mother was also a yandere girl in high school, and killed a female student in one of the school’s bathrooms. The player can actually see the ghost of the girl that Yandere-chan’s mother killed by walking into the bathroom and taking a picture. But what if that ghost had a chance to take revenge on Yandere-chan’s mother, by thwarting her daughter?"
The Phantom Girl can be seen in the girl's bathroom on the third floor.
Coincidentally, there is a rumor that if somebody confesses on a Friday under the cherry tree, which happens to be where the Phantom Girl was located in earlier builds, their feelings would be reciprocated.
- In old builds, Yandere-chan's uniform would take on a black and red color scheme when she touched the Phantom Girl beneath the Sakura Tree. However, that feature is no longer available in recent builds.