The Paralytic Serum makes someone unable to move for five minutes, after which they regain their ability to move and speak.
In Insurgent, the Death Serum was switched for the Paralytic Serum by Peter Hayes in order to save Tris's life at her execution in the Erudite headquarters. It was dyed purple to attain the purple hue of the Death Serum. This is the only use of Paralytic Serum stated in the books.
Tris described going under the serum as:
- "All the muscles in my body relax at once. A heavy, liquid feeling fills my limbs...My eyes stay open, but my head drops to the side. I try to close my eyes, but I can’t—I can’t move."
She also describes being able to breathe; not deeply and not enough to satisfy. The Paralytic Serum succeeded in making Tris look dead in front of Jeanine Matthews, as Jeanine called her a body as she told Peter to take her to the lab.
The effects of the Paralytic Serum are said to only last five minutes.