Backyard Bottomslash (バックヤード・ボトムスラッシュ, Bakkuyādo botomusurasshu) is a 26-year-old bank worker and a victim of the Los Angeles BB Murders.
Bottomslash is drugged before her death, much like Quarter Queen, though her age is 26 years of age, in between the first and second victims. (44 and 13)
Her death occurs nine days after Quarter Queen's; the killer wants to find out if a human can die of an internal hemorrhage without rupturing any organs. This experiment is conducted by drugging and then beating Backyard Bottomslash's left arm without breaking the skin. When this does not work, her right leg and left arm are cut off, and she dies from exsanguination.
The right leg is later discovered in her bathtub, and the left arm is not found at the scene. Two Wara Ningyo are found nailed to the walls in a similar manner as with the other two cases.
- Backyard Bottomslash's initials would be B.B, a reference to Beyond Birthday.