Revelation 8:10-11 - The Third Trumpet
10 And the third angel sounded; and there fell from heaven a great star, blazing like a torch; and fell upon the third part of the rivers, and upon the fountains of waters: 11 and the name of the star was called Wormwood, and a third part of the waters became wormwood; and many men died of the waters, because they were become bitter.