Potential Spoilers Ahead!!! You have been warned!
#1 The Smile Demon and the Smile Dog Creepypasta
The demon or the Smile Entity in the movie may have been inspired from one creepypasta demon called “Smile Dog”. Similar to the nature of the Smile Entity, the Smile Dog, as described on it’s Villains Fandom Page, is an aggressive demonic creature that haunts the person who sees them until they turn insane or commit suicide.
In the original stories, the Smile Dog is a Siberian Husky that carries a very huge and creepy grin on its face. Whenever a person sees the image of the dog, they will be tormented by constant nightmares featuring the Smile Dog. In the dream, dreamers would ask what the dog wants, and the dog will always answer with “spread the word”.
#2 The Smile Demon and the Hym from Witcher
Another fictional demon from the Witcher universe shares some resemblance to the Smile Entity in the movie.
The Hym is a “spectre” type demon present in the Witcher (Witcher 3 Wild Hunt Video Game). Similar to how the Smile Demon feeds on trauma, the Hym lives inside the mind of its victim and will constantly feed on the guilt on their mind, amplifying it to the point where the victim would have so many brutal self-inflicted wounds and then ultimately commit suicide.
#3 Psychological Horror Demon
The Smile Entity is a type of entity or demon that exists exclusively only on the victim’s mind. It is a type of entity whose powers revolves only within the psychological realm, however, it is still unknown whether the Smile Entity could manifest a physical form or not. With its powers, the entity is an extremely formidable foe to be entangled with; since nobody can really help you fight it out on the external side.
Since the play is only inside the mind of the victim, it is nigh impossible to stave off or fight the Smile Entity unless if you are very disciplined with your thoughts.
#4 Zero Weakness, an Absolute Unit
Throughout the events in the movie, there was never one mention of a way to combat or banish the Smile Entity. The only possible way for a victim to escape the grasp of the Entity is that they will need to pass it unto somebody else by making the secondary (next victim) a witness a very brutal killing done by the hands of the current victim.
#5 Fan Guessed Weakness
The Smile Entity would jump from one person to another, using trauma emotion as its bridging link. If the host of the demon dies or commits suicide while no one is around to witness the scene, the demon entity may die. This is the only guess fans on TV Tropes could make on how to kill the demon.
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