: How can I hint that my character isn't real? How can I make a side character's tangibility open to interpretations so the audience is unsure if she's even real? My short story is about identity.

Vote Up Vote Down

You've already begun answering your own question by starting to establish the first critical point for how to deal with hinting at a character who is not what they first appear:

Establishing what they are.

After all, if we don't have a clear view of what they are then it is somewhat difficult to try and drop subtle hints as to what they are...

So what characteristics can we use that an imaginary being has that a real physical one wouldn't? By clearly defining all the characteristics of the nature of your character before writing your story you can use those to decide what hints to lay for your reader. And once we have settled on characteristics we can begin to think about how they can interact [or not] with other characters and the environment.

They're not real, therefore they don't have to respect physics: Maybe allow them to 'shift positions' as described in the scene without moving, or to 'interact' with objects without impacting them.

The character can be sitting in a window booth next to the Main Character offering them hugs, but then are described as leaning over the table to look MC in the face after MC turns to lean against the window.
Imaginary character can be on one side of the room talking about something, and then described as being on the other side of a room to point at an object being discussed.
IC can 'hand' something to MC early in a scene, and then have MC still have to reach for it later.

They're not real, but they're based on the Main Character's own mind, which means their mind and their knowledge of the world is both limited and based on the MC's own thoughts.

They can know something the MC knows when the Imaginary Character wasn't there to learn for themselves. [MC 'goes out', learns something IC shouldn't known, IC then proceeds to discuss things relating to it when MC returns.]

You may also want to carefully consider and research real world mental health issues if you want your story to be highly grounded in reality. Doing so may help you better define the traits of your character and improve how they fit within your story.

In some cases hallucinations of people can be strictly vocal, and not typically present with a visual component. [MC may talk with IC and always describe them as "in another room", or "stretched out on the couch just out of view", but never actually see them or be able to find them.]
A few cases may have hallucinations manifest as memories of interactions from the recent past, rather than being interactions in the here and now.

Reading clinical material on the subject matter may offer avenues to explore that help break away from some of the typical tropes used in past stories as well.

(0)

Vote Up Vote Down

Another alternative is to have other characters question the existing of the friend, accuse the MC of making up stuff, and the imaginary character is never there when the MC could prove their existence.

I have seen this cut in both directions; if the never-there character always has a very plausible excuse for not showing up or for disappearing, they can turn out to be a real person. Or perhaps they just don't want to be seen, because one of her friends might identify them.

A place where an imaginary character played a major role and stayed hidden like this is in Mr. Robot, the TV series, in which the MC Elliot is mentally ill, a split personality that has conversations and physical fights with his dead father, becomes him at times, cannot remember his sister IS his sister and at one point kisses her (which she struggles against), and is often losing his grip on reality. But he's a great hacker.

In the beginning of the first season, to the audience you can't tell that his dead father is not a real person. But then he also thinks he is imagining people that are in fact real.

(0)

Vote Up Vote Down

I would subtly manipulate the dialog so that your main can have scenes where the imaginary character and a real character are both talking and it seems like they are having the same conversation, but not really. For example, the imaginary character asks a question, with the next snip of the real character's dialog responding with what seems like a correct response, but not specifically an answer to a question. If Sarah is your hero, Alice is your imagined character, and Dave is a real character:

Alice: I bet Dave's favorite animal is weird. Probably a Platypus.
Dave: I like polar bears.
Sarah: Really?
Dave: Yeah. They're cool.
Alice: Ooh. That pun hurt.
Sarah: Platypi have nothing on Polar Bears?
Dave: I'm not sure they're even real. I think someone is making them up.
Alice: Now that's a twist.

Note how Alice is responding to Dave, but Dave is not responding to Alice. His initial statement is an unprompted announcement of his favorite animal (maybe they're both at a zoo or trying to make small talk and get to know each other), but his first statement don't mention the platypus at all, he doesn't respond to Alice's comment on the pun, and the first time he states his opinion on the platypus is after Sarah brings it up. While the first two lines certainly look like a conversation between Alice and Dave, it could be that Sarah and Dave have the same idea of a good icebreaker conversation in this situation and Dave makes the statement while Sarah/Alice are still thinking it over ("I was just thinking the same thing!").
The final line is contains both an obvious and subtle joke. Alice reacts to Dave's faux conspiracy theory with a standard meme. This both alludes to M. Night Shamalyan and his famous fictional example I was going to suggest and lightly based the scene on Sixth Sense which has a slightly different twist (one of two good films of his). But it becomes funnier on a "second read" where the audience is aware of the twist of your story. Alice isn't just making casual snark, but foreshadowing the true nature of her character in a way that doesn't spoil it if you didn't know.
Incidentally, the Sixth Sense makes a lot of use of scenes where characters will talk at each other, not with each other. It looks like they are having conversations, but if you actually pick apart these dialogs, they aren't having the conversation or have the same understanding about the discussions. All act perfectly natural given the context of what they think is happening, and all their assumptions about what is happening are valid.

(0)

Vote Up Vote Down

I did this once in a novel-length story. After the first two appearences my wife said that she has a strange feeling with the side character, but couldn't tell why. In the end she was like 'I knew it!'.

What did I do?

I made the side character appear 'just in time', when noone else was around or 'hide' from others for whatever reason. She did always know what was the right thing to say, what the protagonist needed the most in that exact moment, being 'the one she adores'.

So you can make the audience question the existence if nobody else ever talks about this character despite she is somehow always there. You can make her a bit too insightful, give her a bit too much influence on the protagonist, in short: make her feel slightly off without breaking the suspension of disbelief. Just make her totally normal for the protagonist.

(0)