Little Sabitsuki

As you progress through the game, you will find an area with multiple Kaibutsu in their child form, along with multiple regular children. In these areas, you will have the opportunity to see Little Sabitsuki. She's easily recognizable, seeing as she's unique among all other children, and her hair very closely resembles Sabitsuki's (albeit less detailed, given her small stature).

Where to find her
Little Sabitsuki appears in three places:
 * A major appearance in a room where she is lying on her bed, her state changing according to how high your Erosion Counter is. This is also where you can get the Rust Menu type.
 * A minor appearance where she is seen in a plant-grafted state in the past version of the Plant Labyrinth.
 * Her ghost can be found wandering around the Industrial Snow World. It is invisible by default as you have to use the whistle to make her reveal herself.

Connection with the Erosion Counter

As your Erosion Counter goes up, Little Sabitsuki's appearance will also change to fit the overall degree of sickness presently affecting Sabitsuki. She undergoes a total of three stages:
 * Healthy
 * Sick, when the counter reaches 50 points
 * Terminally Ill, when the counter reaches 100 points

Trivia
 * The ghost in the Industrial Snow World is not affected by the Erosion Counter but can be killed with the metal pipe, however.
 * The ghost will also not appear in the Endgame, since as Rust you cannot use any effects, including the Whistle effect which is needed to see the ghost.
 * Several fans find her cute and some felt guilty for having to built up points on the Erosion Counter (which is needed to unlock the Rust Menu) because, when the Erosion Counter is up to 100 points, she is dying from her illness.