Deceased (Presumed by Old Age)
September 24, 1988
Lois played by actress Hallie Foote is the mother of Julie and the grandmother of Katie and Kristi. Lois only appears in Paranormal Activity 3. However, her presence is also referenced in Paranormal Activity: The Marked Ones in a picture.
It is implied that she made a deal with a demon for wealth and fortune which she forfeited the life of a first male child that would be born on her side. The debt was not kept until after her death when her granddaughter, Kristi, became pregnant with her first child, Hunter. However, this is unsubstantiated within the series and another competing theory assumes a relative in the 1930's made the pact since Ali is recorded as saying that Hunter is the first male child in the family since that time.
On September 3rd, 1988, Lois appears in the beginning at Katie's birthday party. She gives birthday wishes via camera with Dennis.
On September 15th, 1988, Lois comes to visit her house and they converse about her daughter about her former husband, her new boyfriend, the girls, and more importantly, other children she may have wanted in the past. Lois tell her how she always said before she always wanted a "big family". Julie then tells her that she changed her mind and is satisfied with her two beautiful girls, Katie and Kristi. She was trying to convince Julie of trying to bear a son (for the purpose of the demon).
On September 24th, 1988. Julie, Dennis, Katie and Kristi all go to Lois' house to get away from the Demon when more demonic activity begins to happen. Dennis sees Lois with a group of women in the shed and tries to run away. Later, when Dennis is thrown on the floor by the Demon he begs for Lois's help, but she just smiles as Dennis' spine snaps itself, killing him instantly. Lois then proceeds to go upstairs while holding Katie and Kristi's hands.
It is revealed on Wikipedia and several other sites that the ending of Paranormal Activity has been explained, Lois was part of a cult of women who made dealings with demons for materials. The elderly women who were in the shed were in fact the cult who were about to perform a dealing. After Dennis and Julie were killed Lois and the cult performed a deal that the Demon would haunt the first person in the next generation to give birth to a son, so in the events between Paranormal Activity 3 and Paranormal Activity 2, Kristi becomes pregnant with a baby boy, who she names Hunter. (The demon) stays with Lois until she dies and moves onto haunting Kristi, then Dan makes a deal with a Demon to send it to another family member, Katie which is the start of Paranormal Activity. Katie is possessed so she then murders Kristi and Dan and abducts Hunter.