Revelation 6:4 (NIV): Then another horse came out, a fiery red one. Its rider was given power to take peace from the earth and to make people kill each other. To him was given a large sword.
Interesting, I assumed it was exposure to a chemical just like the pink elephants. Yes there are such things it happens in Africa where they have a "dust bath" in a type of red dust (they should go to Central Australia) the first reports seemed so ludicrous that it became synonymous with someone who had taken on too much alcohol.
