Almost every kid grows up with an imaginary friend, which is why so many TV shows include a character who also speaks with an imagined companion. But unlike most kids in real life, these imaginary friends aren't exactly innocent. Whether they are created by childhood trauma, ghosts of the dead, or some other cause, these imaginary characters are often some of the most important people on the show.
Harry Morgan, "Dexter"
We all know Dexter is disturbed; he is a serial killer, after all. One of the hallmarks of the show is the way that Dexter has a conversation with his dead father, Harry, in almost every episode. In an effort to live up to his father's code of ethics, Dexter often has a dialogue with his psyche's imagined version of his father. This season, Dexter developed a second imaginary friend: his murdered brother, Brian.
When Hurley was in a mental hospital, his best pal was a guy called Dave who always tried to talk him into escaping, overeating, and other unhealthy activities. Hurley eventually decides that Dave isn't real and soon begins to recover. Dave eventually shows up on the island where he tries to argue that the island, and not himself, is what Hurley is fabricating. But since we eventually learn that Hurley can talk with the dead, it could mean that Dave was real after all, or at least a real person that the island took the form of.House, "House"
Toward the end of the fifth season of this Fox drama, House starts hallucinating that Amber is stalking him. House, as a reasonable doctor, decides that the hallucination represents unbridled access to his subconscious, and starts to listen to what Amber has to say. Things take a turn for the deadly, however, when Amber's arrangements for Chase's bachelor party cause him to have an allergic reaction to some food. House then starts to descend into madness and is eventually committed.The Doctor, "Doctor Who"
The Doctor isn't really an imaginary friend, but all of Amy Pond's friends and family (and psychiatrists) try to convince her that the "raggedy doctor" is all just a figment of her imagination. The Doctor takes it all in stride however, and when he shows up at Amy's wedding, he announces, ""Hello, everyone! I'm Amy's imaginary friend... but I came anyway."Maggie, "Supernatural"
In the episode "Playthings," we meet two little girls: Tyler and Maggie. As the story progresses, we discover that Maggie is Tyler's imaginary friend. What's more, Maggie is actually the ghost of Tyler's great aunt, who died in the house many years ago.