Fear Projection

Fear Projection is the ability to sense and read the fears of other beings and use it against them. This power is unique to the demon Barbas, and is known as the demon of fear because of it.

Overview
The first and most basic application of this power is sensing or reading the fears of other beings. An example of this happened in 2004, when Barbas read Gideon's worst fear and then promised to tell no one.

Projecting fear into reality
Barbas can read the fears of other beings and then projecting it into reality. Doing so will send their fear into overdrive, as they are forced to experience their greatest fear, paralyzing them until they die of a heart attack.

The change in reality can sometime cause injury to the victim, as in the case of Tanjella. However, in Zoe's case, she suffered no other injuries other than a heart attack when he trapped her in a circle of fire.

In 1998, Barbas tried to kill Prudence Halliwell by using her fear of drowning against her. However, Patty came to her rescue and helped her to overcome her fears. This act neutralized Barbas and sent him to purgatory.

Brainwashing
On Friday the 13th in 2000, Barbas returned and attacked Prudence again. However, this time he used his powers to brainwash her based on her fears; which was "losing a sister", since she had already conquered her fear of drowning. Barbas tells Prue that demons are masquerading as her sisters and she must kill them before they kill her real sisters. Fortunately, Phoebe and Piper were able to break the brainwashing by talking to Prue and getting her to believe that they were in fact her sisters.

Creating illusions based on fear
Barbas can also create realistic illusions base on a person's fears. His illusions may be limited to visible manifestations that affect only sight, or affect all the five senses so that they cannot be distinguished from reality.

Barbas usually employ this method when he's attacking people within a group, presumably because he has to attack them individually because each persons fear is different. However, it is just as effective as projecting someone's fear it into reality, because the victim will think the illusions are real.

In 2000, Barbas uses this aspect of his power to scare D.J by forcing him to witness an illusion of his greatest fear, which was Bane Jessup shooting him. Afterwards, illusion-Bane disappeared as well as D.J's illusionary wounds.

Subliminal Messaging
After learning how to astral project onto the astral plane as an invisible spirit in 2002, Barbas began to use subliminal messaging as a form of attack. First, he reads his victims fears, and then project as an inner voice to them, preying on their fears and doubts, and then reinforce that by creating illusions within their mind.

Barbas could also use this form of attack to manipulate his victims into fulfilling his aims. For example, he used subliminal messaging to trick Paige into stripping Cole of his powers so that he could steal them.

This form of attack allowed Barbas to attack and manipulate his victims without them ever being aware of his presence, as well as attack them from a distance.

Tracking with fear
In 2004, Barbas revealed to Gideon that he could track people with their fears when suggesting ways of how to track down Wyatt.

Season 3
In Darkness is Here, Barbas is mentioned by Gadreel as infamous and very popular "up there". The Angels had told Gadreel about Barbas while he was trapped, so when he was released he decided to bring the Demon of Fear back to live. He gave Ignatius the task of finding Barbas, and he succeeded. Barbas is officially back from the dead and working with Gadreel.

The episode Tell me what's your Fear, I'll tell you how you'll Die, is set to focus on Barbas' return and him going after the Destined Ones. He projects all of the Destined One's fear, and all but Chris and Wyatt are able to overcome them. He succeeds in killing Wyatt but is stopped by Gadreel before he can kill Chris as well.