Nightmare Fuel / The Host (2006)

• When the trapped Hyun-seo and Se-joo witness the creature regurgitating a very large load of human bones and dead bodies back down into the sewer.
• When the monster goes to swallow Hyun-seo and Se-joo, and it cuts to black while all we hear is Hyun-seo screaming.
• Hyun-seo's capture by the creature.
  • As is Hee-bong having one of his children torn away from him by government agents.
• The gangsters Hee-bong buys the truck and the map from are pretty intimidating.
• Gang-du getting tissue samples taken from his neck is rather uncomfortable to watch, especially for those who hate hospitals.
• Gang-du's lobotomy. It all happens offscreen, but we do see him strapped to an operating table by doctors, helpless and tearfully begging for the absent Hyun-seo's forgiveness.
• The death of Gang-du's father. Particularly when the creature throws him with its tail and smashes his skull on the riverbank.