Nightmare Fuel / The Ruins

  • There is a very good reason why the locals maintain such a strict perimeter around the ruins... too bad the protagonists don't learn why until it's way too late.
  • The plants themselves are clearly nightmare fuel for the locals. They're mobile, carnivorous, and infectious. If you touch them, well, you're boned. Anyone that touches them gets a prompt Mercy Kill - or is simply herded to the top of the ruins to wait for the plants to do their work.
  • The scene where they search for the "cell phone" by following the noise, before realising it's the plant mimicking the noise to lure them closer into a trap.
  • When the plants start mimicking Stacy with all of them saying "I want to cut it" over and over and over again as she is filleting her own leg.
  • The amputation scene. It goes on for a very long time, with characters trying to smash and splinter gristly bone after the rest of the surrounding flesh has been hacked away - with no anesthetics whatsoever. To prevent bleeding out, they try cauterizing the wound with a pan that had been sitting on a fire. The character dies anyway, because they left him by the plants and were too busy arguing to notice what was going on.
http://tvtropes.org/pmwiki/pmwiki.php/NightmareFuel/TheRuins