Revelation 8:10 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; 11 And the name of the star is called Wormwood: and the third part of the waters became wormwood; and many men died of the waters, because they were made bitter.

Everyone thinks this passage is about a star/asteroit/comet hitting earth and that may happen.

Still I submit this is a angel/devil. In the bible stars represent angels and the seas/water represent people making them bitter.

Relveation 17:15 Then he said to me, “The waters which you saw, where the harlot sits, are peoples, multitudes, nations, and tongues.