The Demon is the main antagonist of the Paranormal Activity film series. The demon haunts the families of two sisters, Katie and Kristi. The Demon is then revealed to be called Toby (though he may have just said it, to not be recognized).
The demon's appearance is a blackened figure with long hair. The demon can be seen in the trailer, Katie and Kristi perform Bloody Mary, in Paranormal Activity 3 on several occasions:
- Dust falls on the demon during an earthquake, the demon moves and the dust falls to the ground.
- Under a white bedsheet which is thought to be either Katie or Kristi but is revealed not to be when the sheet collapses revealing no-one beneath.
- Behind Dennis whilst at Katie and Krisit's grandmothers house, the demon is in the background for a few seconds and then dissappears when Dennis picks up the camera.
- Present as a shadow on a window, Dennis goes into the room from which the shadow is being cast and finds nothing there.
The demon also possesses Kristi and Katie's grandmother, Katie as an adult and as a child, and Kristi as an adult and as a child.
In Paranormal Activity 4, some instances can show the demon as an invisible child figure, though some blackened figures are also been seen.
This and the scenes, in which Wyatt (Hunter) is speaking with something in the living room, that appears bigger than an average human, while something of child-like statue is sneaking up on him from behind (made visible by the infrared dots), might tell us that more entities might be involved. You can also see the child-sized entity when Wyatt(Hunter) and Robbie are running around the house at night. In the last shot as they run through the living room where the projection dots are still on, you can see the "entity", followed by Robbie, then Wyatt(Hunter). It's hard to notice it if you're not paying attention right as the lights are turned on by the mom. The scenes from this angle bear more visible clues of this kind. In one shot, for example, something seems to get closer from the top right corner of the picture (the kitchen area), while Robbie is already talking to something in the spot the bigger entity appears to be later. It still might be possible that a single entity caused all this, but it often looks like there are more beings involved during Paranormal Activity 4.
The demonic figure is also seen in the 'What Really Happened' trailer, behind the unknown girl. She appears to not notice it, but it seems like the unknown male on the video chat sees him and tries to warn her before the door slams.
At the end of Paranormal Activity: Ghost Dimension the demon takes on a physical form.