The Spine is a large, worm-like creature that appears in certain parts of the game. It has a large, sharp tail which it uses to stab at the player as they progress through various areas. This tail can teleport through walls, is invulnerable to any damage, and is the only part of the Spine that attacks the player outside of the boss battle.
The Spine's head consists of several 'eyes' and a 'mouth' that it uses to spit out damaging projectiles at Red, and only makes it's appearance during the boss battle.
After the Spine is defeated, it is then shown that it has 'insides' made up of red, black and white designs typical of the Process, as well as a vulnerable 'heart'-like structure.
- The Spine seems to have a negative effect on the Transistor, causing it to glow red and the soul voiced by Logan Cunningham to grow static-filled and become confused, in a manner similar to alcoholic inebriation. During the boss fight, the effect grows until the voice disappears completely. There is little reason given for this effect, other than the soul suggesting that the Spine's large size and proximity makes the effect potent enough to become noticeable. Entering the Sandbox temporarily removes these effects.
- The Spine is shown to be just one of many - after defeating the Spine and exiting Asher and Grant's office, there are several Spine's flying about in the background of the following cutscene. Another Spine also attacks Red as she makes her way towards Fairview, though it can't be killed.