This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Across the Universe
The army segment of "I Want You (She's So Heavy)".
Naked Vietnamese women who do a weird kind of gymnastic dance thing while standing in water about three feet deep, presumably near a beach... and then fall over dead for no apparent reason. Then we're treated to a lovely shot of dead naked bodies with water washing over them.
Orion's death is the nastiest in the series by far. After being frozen without the proper preparation, he comes out blinded, with severe tissue damage (squickily described as being like a wet sponge), and dies within minutes.