I was watching Stephen King's Graveyard Shift last night, the greatest rat based horror movie ever(eat it Willard!) and I thought while we only get 90 minutes of them wading through filth and water, they must have done it for at least a month or two, which must have really sucked. Imagine floating in filthy water surrounded by rats for hours and days. Not real people suck obviously, but still pretty nasty.
So that got me thinking, what other genre movies do you guys think would have been nightmares to shoot, because of conditions, physical demands, or just pure insanity of the plot?