<Tr> <Td> Put down / put to sleep </Td> <Td> To be euthanised </Td> <Td> Euphemism </Td> <Td> Euthanasia of an animal </Td> </Tr> <Tr> <Td> Put one to the sword </Td> <Td> To kill someone </Td> <Td> Literary </Td> <Td> </Td> </Tr> <Tr> <Td> Rainbow Bridge </Td> <Td> Dead </Td> <Td> Euphemism </Td> <Td> Usually referring to the death of a pet, i.e. "Crossing the Rainbow Bridge ." </Td> </Tr> <Tr> <Td> Ride the pale horse </Td> <Td> To die </Td> <Td> Euphemistic </Td> <Td> In the Biblical passage Revelation 6: 8, a pale horse is ridden by Death, one of the Four Horsemen of the Apocalypse . The expression "behold a pale horse" has been used as the title of a 1964 film by Fred Zinnemann and a 1991 book by ufologist William Milton Cooper . </Td> </Tr>

Where does the saying dropping like flies come from