Deranged serial killer Ruth Lacey
Ruth Lacey (Anna Walman) was the titular main villainess from the 2017 film, Housewife Alien vs Gay Zombie.
Ruth Lacey was the deceased sister of Catherine Lacey, though prior to her passing, she had become an alien serial killer bent on murdering people who (in her mind) showed bad manners. In the film's events, Catherine--who missed her sister--agreed to align with Barboura, the body-less wife of mad scientist Dr. Morris, in a scheme to resurrect her sister, which involved acquiring the ingredients to grow a particular plant. The result saw Ruth return in the form of said plant, but in order to regain a body, Ruth seduced and engaged in a sexual encounter with a woman named Judy as part of her own scheme.
As a result, Ruth was reborn through Judy, who she killed by emerging from Judy's body. Following her resurrection, the villainess continued her killing spree, which included crashing a party and murdering several of the guests, and later killing an operator who Ruth felt was rude to her. The climax saw Catherine horrified at the realization that her sister was nothing more than a sadistic and maniacal serial killer, and during a zombie rampage, Ruth was killed by Catherine, who fired a laser gun at her deranged sister.