This theme had gradually been dropped in later seasons, starting with it's peak in the two-part season 6 finale, "Stewie Kills Lois" and "Lois Kills Stewie", where Stewie created a virtual reality headset that displayed to him an extremely realistic and overly detailed example of exactly what would happen if he killed Lois and the outcome was not good. Lois was not actually killed. Stewie just thought she was and Lois came back and killed Stewie. This convinced Stewie to stop trying to kill Lois. Although for some reason, the next two seasons saw Stewie still making a significantly smaller number of murder attempts on her. By the time the ninth season rolled around, the arc of Stewie trying to kill his mother was completely dropped and the concept was only revived in brief mentions, all of which were geared toward making a meta joke about how Stewie never does this anymore.