Munitorium Swamp Warfare instructors may tell you the swamp is your friend. More realistic instructors may claim it's just neutral. Let me tell you; the swamp is not neutral and it most certainly is not your friend. It's your enemy, and you'll soon learn to hate it.
— Rifleman Tyla, Pardus 34th Regiment, Warhammer 40,000
Other kings said it was daft to build a castle in a swamp, but I did it all the same, just to show them. It sank into the swamp. So I built another one. That one sank into the swamp. So I built a third one. That burned down, fell over, then sank into the swamp.
— The Swamp King, Monty Python and the Holy Grail
Mangus: I don't like all those nooses...
Zaulia: They're for those who would rather take their own lives than be destroyed by the creatures of the mire.
Eddie: See? A service for travelers!
Sam: There are dead things! Dead faces in the water!
Gollum: All dead. All rotten. Elves and Men and Orcses. A great battle, long ago. The Dead Marshes... yes, yes, that is their name. This way. Don't follow the lights. Careful now... or hobbits go down to join the dead ones, and light little candles of their own.
The Lord of the Rings: The Two Towers, film version
From the shores of the northern Tilean sea to the foot of the Black Mountains, a great morass of dismal marshland lies like a festering plague. This area is known as the Blighted Marshes: an ancient and terrible realm where death comes quickly to the unwary. A permanent, reeking mist cloaks the deep black pools and slimy reed beds from view. Sluggish, muddy channels wind through the mire, mazelike and unfathomable, darkened on either bank by stretches of stretches of twisted stalks which resemble nothing so much as corn blackened in a fire. In places, pools form, slicked with a dark iridescence where no living things grow. To enter the Blighted Marshes is to walk to your doom, inviting death in the bottomless murk or the jaws of the twisted beasts said to live there. Few brave its terrors, for there are no tales of gold or hidden knowledge lying forgotten in its chill clutches to draw adventurers, just black marsh, reeking mist and a lonely death.