3) The NeverEnding Story (1984)
The NeverEnding Story's Swamp of Sadness was more than a monicker (or a cautionary tale that could be chalked up to superstitious hearsay), the mire literally was a mud pit of tears feeding off travelers' sadness. So more disturbing than Artax being swallowed up by the muck—why did it have to be so painfully drawn out?—was the fact he was letting his own despondency over the situation consume him. In other words, Artax essentially gave up on life. Who knew horses were capable of such complex thought?