Third Trumpet
The Star Wormwood
Revelation 8:10-11

"And the Third Angel sounded, and there fell a great star from heaven, burning as it were a lamp, and it fell upon the third part of the rivers, and upon the fountains of waters; and the name of the Star is Wormwood: and the third part of the waters (rivers) became wormwood, and many men died of the waters, because they were made bitter."