Rock (Symbol)
At the beginning of the film, Ki-woo's friend, who is wealthier and goes to college, gives the Kim family a special rock, which is meant to bring wealth and prosperity. As the Kims begin working in the Park house and making more money, the rock becomes a symbol of their newfound luck and growing prosperity. By the end of the film, after Geun-sae has bludgeoned Ki-woo with the rock and Ki-woo has recovered, the rock becomes a more complicated symbol, a symbol for his desire for upward class mobility that was thwarted and ended in violence. As Ki-woo places the rock in a river, we see him taking a more subdued relationship to his own dreams of wealth. The rock now symbolizes Ki-woo's desire for a better life in so far as it offers him the possibility of a reunion with his family.
Underwear (Symbol)
In order to get the Parks' driver fired, Ki-jung plants a pair of her own underwear in the back of the car, to make it seem like the driver had sex with someone in the backseat. When Mr. and Mrs. Park find the panties, they speculate about all the sordid things that the driver might have done in the backseat. As Mr. Park observes that the underwear's placement in the backseat suggests that the driver had sex in the backseat rather than in the front, the underwear becomes a symbol for the perversity of the driver in the eyes of the Parks. The underwear is at once an arousing and repellant object, which excites the Parks' sense of disgust as well as their sense of fantasy. Later, they role-play as the driver and his mistress while sleeping on the couch.
Moon-gwang's video (Symbol)
After Moon-gwang discovers that the Kims are all related to one another, she takes an incriminating video of them arguing as a family and threatens to send it to Mrs. Park. The video becomes a symbol of her power over them, and she exploits it as a dictator would. She and Geun-sae make the Kim family do their bidding, their fingers hovering over the "send" button, as Geun-sae compares the button to a North Korean missile launcher. The video, and the blackmail power it has, represents something like a war and a tense struggle for survival.
"Crossing the line" (Motif)
Mr. Park is somewhat obsessed with the concept of "crossing the line" and it is a guiding principle when it comes to how he relates to his employees. When he believes his driver has had sex in his backseat, Mr. Park is horrified by the idea that he would "cross the line" by going to the backseat, where he, the employer sits. Then, when he hires Ki-taek, he comments favorably on the fact that his new driver never "crosses the line." This turn of phrase is a euphemism referring to an employee's ability to know their place, and not presume to be on an equal plane with their employer.
Parasite (Allegory)
The title gives the plot of the film an allegorical frame, suggesting that the dynamics that arise within the narrative are parasitical. The most obvious parasitical relationship is that between the Kims and the Parks. The Kims lie in order to all begin working in the Park household, and live off the wealth of the Park family, which in turn trickles down to them. In this sense, they are "parasites." Additionally, Geun-sae is a parasite, in that he lives in the secret bunker in the Parks' house and steals food from them. Finally, the Parks are parasites as well, in that they rely on the labor of others in order to live. They do not cook for themselves, clean, or drive themselves places. In this way, each of the characters is a parasite in some way.
