User with this ability either is or can transform into a mental entity, or an entity of pure mental energy. Users' transformed form is anatomically identical to their normal form, aside of being made of energy, in which case, it contains all to organs and is somewhat vulnerable to attacks. Alternately, the user can transform into homogeneous matter, without any part of their form being more important than the other.
Users are bound by the rules and physics of the mental plane, and cannot exist in the real world.
May be unaware that they are simply concepts and not actual people.
May be unable to do anything other than what they are manifestations of.
The mind that they influence may be able to eradicate them naturally.
Known Users
Live Television/Movies
Demonic Carl Stargher (The Cell)
Members of the Psyche (Herman's Head)
Angel
Animal
Genius
Wimp
Riley's Emotions (Inside Out)
Joy
Sadness
Anger
Disgust
Fear
Bing-Bong (Inside Out)
Jangles the Clown (Inside Out)
Tommy Oliver's former Ranger identities (Power Rangers: Dino Thunder)
Green Ranger
White Ranger
Red Zeo Ranger
Cartoons
Pizza Jenny (Steven Universe)
Id (Duck Dodgers)
Ego (Duck Dodgers)
Superego (Duck Dodgers)
Eros (The Venture Bros.)
Thanatos (The Venture Bros.)
Id (The Venture Bros.)
Dead Sons (The Venture Bros.)
Invisible Harem (The Venture Bros.)
Ego (The Venture Bros.)
Superego (The Venture Bros.)
Anime/Manga
The Beast of Darkness (Berserk)
???% (Mob Psycho 100)
The Little Ogre (Soul Eater)
Video Games
Shadows (Persona 3 & 4)
Censors (Psychonauts)
Personal Demons (Psychonauts)
Nightmares (Psychonauts)
Party Dancers (Psychonauts)
Lungfishopolans (Psychonauts)
Kochamara (Psychonauts)
G-Men (Psychonauts)
Rainbow Squirts (Psychonauts)
The Milkman (Psychonauts)
Becky (Psychonauts)
Jasper Rolls (Psychonauts)
Napolean Bonaparte (Psychonauts)
Dingo Inflagrant (Psychonauts)
Doppelgangis (Realms of the Haunting)
The Luchadores (Psychonauts)
Lampita Pasionado (Psychonauts)
Oleander's Father (Psychonauts)
Augustus Aquato (Psychonauts)
The Creep/Harlan Wade (F.E.A.R. 3)
The Keeper (The Evil Within)
The Administrator (The Evil Within: The Assignment)
The Blood/Inner Dracula (Castlevania: Lords of Shadow 2)
All residents of Wonderland (American McGee's Alice)
Other
Inner Intellects (Channel Awesome)
Inner Jocks (Channel Awesome)
Fallen Hana (Me!Me!Me!)
Gallery
Comics/Cartoons
While exploring Duck Dodger's mind, the team comes across his Id (Duck Dodgers). Because Dodgers has little to no self control, his Id is left underdeveloped enough to where it looks and acts as a Neanderthal, too dumb to spell his own name right.
While exploring Dodger's mind, the team encounters his Superego (Duck Dodgers). While the Superego manifests as a superhero, he is clearly incompetent at his job, making Dodgers callous and self-centered.
Because Duck Dodgers values himself so highly, his Ego (Duck Dodgers) manifests as a smooth, James Bond-type character.
Pizza Jenny (Steven Universe) is the manifestation of Kiki's sister Jenny in Kiki's mind and is the source of her recurring nightmares.
When Orpheus ventures into Rusty's mind, he comes across Eros (The Venture Bros.)…
…and Thanatos, his sex and death drives.
Rusty's Dead Sons (The Venture Bros.) are zombie-like manifestations of the many dead clones of Hank and Dean weighing on his subconscious.
When exploring Rusty's mind, Orpheus encounters his Id (The Venture Bros.), his hedonistic side.
The Invisible Harem (The Venture Bros.) are mental manifestations of women Thaddeus Venture has dated and/or had carnal feelings for.
While exploring Rusty's psyche, Orpheus encounters his Ego (The Venture Bros.). Because Rusty sees himself as a failed inventor and scientist, his Ego manifests as a calm, if not sarcastic Geppetto-type character, struggling and failing to repair his inner child.
When in Rusty's mind, Orpheus encounters the Superego (The Venture Bros.), the one righteous part of Rusty's mind.
Bing Bong (Inside Out) was Riley's imaginary friend that still lived within her mind.
Jangles the Clown (Inside Out) is a monstrous clown deep inside Riley's Subconscious, manifesting as an evil entity and is one of Riley's biggest fears.
Anime/Manga
The Beast of Darkness (Berserk) is the manifestation of all of the rage and hatred in Guts's soul as a result of the hellish ordeal of the Eclipse, and his feelings of vengeance against Griffith and the God Hand for what they have done to him. The Beast wants Guts to throw his humanity away and become a monster like those he fights.
???% (Mob Psycho 100) is the subconscious manifestation of Shigeo Kageyama's psychic power, which was consciously repressed in order to appear normal.
The Little Ogre (Soul Eater) is the manifestation of the black blood in Soul's mind, goading him to give in to his inner madness.
Live Television/Movies
Due to his abuse as a child, Carl Stargher (The Cell) develops into a serial killer, his murderous impulses manifesting as a demonic version of himself within his mind.
After being rendered comatose by the destruction of his Dino Gem, Tommy Oliver (Power Rangers Dino Thunder) confronted three of his former Ranger identities within his mind.
Video Games
Censors (Psychonauts) are beings within the mental world that hunt and "stamp out" any manias or foreign forces that invade one's mind, keeping them sane.
Kochamara (Psychonauts) is a mental broadcast from Oleander into Linda's mind as a means to control the monstrous lungfish.
The G-Men (Psychonauts) are beings within Boyd Cooper's mind that actively search for the Milkman, hoping to uncover the entity hidden deep in Boyd's subconscious.
The Rainbow Squirts (Psychonauts) are beings psychically planted in Boyd's mind to keep the Milkman hidden away until he is summoned...
...led by the Den Mother.
The Milkman (Psychonauts) was an alternate personality planted in Boyd Cooper's mind charged with burning down the asylum when a specific trigger phrase is given.
Jasper Rolls (Psychonauts), also known as "The Phantom", is the source of Gloria's psychosis.
Napolean Bonaparte (Psychonauts) is a genetic memory responsible for Fred Bonaparte's psychosis.
The Luchadores (Psychonauts) are manifestations of Edgar's old high school wrestling team found within his mind.
Dingo Inflagrante (Psychonauts) is based after the varsity cheerleader that stole his girlfriend, is one of the sources of Edgar's psychosis.
Lampita Pasionado (Psychonauts) is based off of his high school girlfriend, is one of the sources of Edgar's psychosis.
Because of the way he treats Razputin, Augustus Aquato (Psychonauts) manifests from his son's mind as a being who tries to kill him.
Because of the trauma he put his son through, Oleander's Father (Psychonauts) manifests as a personal demon within his mind, and is the source for all of Oleander's evil behavior.
The Keeper (The Evil Within) is a manifestation of Ruben "Ruvik" Victoriano's rage at the theft of his files from his personal safe by Dr. Marcelo Jimenez, made real in the STEM mental-scape.
In order to keep Juli set on her mission, MOBIUS injected her with a serum that manifests in her mind as the Administrator (The Evil Within: The Assignment) a black, shadow-like entity that haunts her throughout her mission.
The Queen of Hearts (American McGee's Alice) is the manifestation of Alice's madness, made into her monstrous form after the death of Alice's family in the fire.
Dollmaker (Alice: Madness Returns) is the manifestation of Dr. Angus Bumby's influence on Alice and is the source of Alice's returning madness.
The Corrupting Blood (Castlevania Lords of Shadow 2) is the manifestation of the lonely castles haunting revenant that manifested the attributes of Gabriel's maddening bile and venomous hatred towards god in physical form, taking shape as Inner Dracula turning the castle itself against him to become whole with it's counterpart once again.
Other
The Inner Intellects (Channel Awesome) are the part of one's mind that deconstructs the parts of movies that appeals to one's intellect, such as sound design, visual design and philosophy...
...while the Inner Jocks (Channel Awesome) focus more on the more base appeals, including awesome action scenes, awesome characters and gore in horror films.
Fallen Hena (ME!ME!ME!) is a dangerous and dark mental entity that thrives on the modern sexual addictions and perversions.