Lake - A lake is home to drowned children and vengeful spirits. Do not think about taking a small wooden rowboat across a lake and falling asleep, because when you awake a demon child will drag you beneath the surface and eat you. Alternatively, you should not stay the night at a cabin by the lake as you will be stalked by a knife-wielding maniac.
Lycanthrope - What would usually be called a werewolf, is now called a lycanthrope, due to fans of Twilight and other assorted monstrosities. A lycanthrope is a wolf that has the ability to change into a long-haired nancy-boy that has a fetish for high school girls. To kill a lycanthrope, give Jack Nicholson a call and tell him to watch Twilight: New Moon. The prolific actor will fly into a inconsolable rage and proceed to extinguish all emo-related wolf-boys on the planet.
London - The capital city of Victorian killers. Whether having a hair cut or just trying to eke out a modest living by having sex with men for money, a victorian killer will find you and cut your throat with a razor blade. Then a group of roguish children with flatcaps and bad teeth will rob your corpse.
Leprosy - If one of your friends starts to fall apart piece by rotting piece, then they may have leprosy. You should ostracise them immedietly, perhaps finding some sort of 'colony' where they can be among their own kind, lest they infect you with their dirty devil-plague.
Lead - If you need to hide from an evil Super Hero, such as Super Man in that one film where he flicks peanuts in the bar, then you should find a shed made of lead. A super hero cannot detect you in a lead box and thus will not kill you. The lead poisoning will do that...
Leroy Clinton - Bill Clinton's secret lovechild with Bill Cosby, who happens to secretly be an elderly black woman pretending to be a lovable male comedian. Leroy Clinton is a republican and an avid supporter of equal rites in America.
Lunatic - There are two types of a lunatic. The first is a crazy homeless person that warns you about some impending doom; these lunatics should be listened to because ten years before they were the world's leading scientist in Applied Astro Physics hunted down by a shadowy corporation and forced into hiding. The second kind of lunatic will hide his face and carry a knife. You should ignore any advice given by these types of lunatics and instead run away.
Lust - Lust will get you killed in a horror movie - especially if Kevin Spacey is going around killing sinners. You should refrain from lust and instead devote yourself to the pursuit of scientology. Tom cruise never dies in movies and this is because of his belief that we all descended from space robots...or something.
Lump - Lumps on your body are not good and you should get them checked out. Chances are is that they are filled with evil alien parasites, waiting to burst forth and infect the earth. You should use a reliable topical cream and wash regularly with a anti-allergenic loofer.