Visine could be used as a poison in a mystery story. A character might put Visine in someone's drink, and the victim would start showing strange symptoms like excessive tearing, blurred vision, and nausea. This would then set off a chain of events where the detective has to figure out what's wrong with the victim and ultimately discover the use of Visine as the cause.
Visine could play a role in a horror story. For example, a group of teenagers breaks into an abandoned house. One of them finds a bottle of Visine and, out of curiosity, uses it. But this Visine has been cursed or contaminated. After using it, they start seeing terrifying visions that are slowly driving them insane, and the rest of the story could be about their struggle to escape the house and the curse.
Lingerie can be used as a plot device by creating a situation of anticipation. For example, a character is waiting to see their partner's reaction to a new lingerie set, which builds tension. It can also be used for misdirection. Maybe a character assumes another's intentions wrongly based on their lingerie.
Amnesia is often used to create mystery. For example, in a detective story, when a witness has amnesia, it makes the detective's job harder and adds suspense as they try to help the witness regain their memory to solve the case.
One way is through the creation of elixirs. In some novels, an alchemist creates a special elixir that can grant immortality or superhuman abilities. This becomes the center of the plot as different characters fight to obtain it.
Food can be poisoned to kill or incapacitate a character, which is a simple yet effective plot device. For example, in many classic crime stories, the poisoned cup of tea or a spiked dish is a common trope.
Braces can be used to show a character's insecurities. For instance, a girl in a young adult novel might avoid social situations because she's embarrassed about her braces. This drives her character arc as she overcomes this insecurity.
It can be used to create mystery. For example, if a character is seen fingering a strange mark on a wall in the school hallway, it can pique the curiosity of other characters and the readers, leading to an investigation within the story.
Soap can be used as a plot device in a Christmas story by creating a mystery. For example, a special soap that has a unique smell might be left at someone's doorstep on Christmas Eve. The characters then try to figure out who left it and why. It could lead to a heartwarming discovery about a secret Santa or a neighbor who is trying to spread Christmas cheer in an unusual way.
A mask can be used to create mystery. If a character is always wearing a mask, the readers will be curious about what's beneath it. This can drive the plot forward as the story unfolds to reveal the truth about the masked character.
A loaded gun can be used to introduce conflict. If two characters are in a room and one discovers the other has a loaded gun, it immediately creates a power imbalance and a source of conflict. This can be the starting point for a tense and engaging short story plot.
It can create mystery. For example, if a character starts to have strange feelings towards a new acquaintance who looks like their parent, it can lead the reader to wonder what's going on. This draws the reader in.