A Fetus

The Fetuses (胎児) are creatures which look like red demons with teeth on their faces and stomachs, and they seem to have something like antennas or horns on their heads. When the player controls Rust, Fetuses replace the Kaibutsu, but move faster than those, and also appear in places where there were no chasers previously. There is no calm Fetus variety, they all chase after the player, but there are special large Fetuses, appearing only in Rust's version of the Corrupted School.

When Sabitsuki uses the Television effect in the Womb Maze's special areas, the only place where she can meet Fetuses, the screen always shows an image covered with either rust or blood. Contact with one of these creatures causes Sabitsuki to cancel her equipped effect. Rust takes damage when she is touched by a Fetus, and if damaged 15 times per one flow session, she will collapse and wake up in the real world. The large ones kill Rust on touch. Also, touching a Fetus as either Sabitsuki or Rust increases the Erosion Counter by 3 points.

Most Fetuses cannot damage Sabitsuki or Rust if the menu is inaccessible for the player. The large Fetuses are unaffected by this.


  • Fetuses are named after the in-game switch that affects the Television effect in areas where they are present.
  • When the large Fetuses were introduced, they were actually harmless. This was because all Fetuses were programmed to not damage the player's character if the menu is inaccessible for them, like in the Corrupted School. This condition was removed for the large Fetuses in the following updates.


  • Some theories state that these represent some type of disease that is plaguing Sabitsuki's body as they are originally only found in the Womb Maze, then begin to populate the rest of the worlds after the Onigo start dying off in mass.
  • Since they are called Fetuses, and initially can be found only in the world that resembles a womb, it is possible that Sabitsuki was, or is, pregnant. It is possible that this pregnancy was unwanted, since there is an area that implies prostitution, and this might be the reason why Sabitsuki sees Fetuses as demons.