Revelation 8:11

And the name of the star was called Bitterness. And a third part of the waters became bitter, and many men died by the waters, because they were bitter.

Hebrews 12:15

taking care that no one may come short of the grace of God, that no root of bitterness springing up may make trouble and by it many be defiled,

Revelation 8:7

And the first sounded; and there was hail and fire mingled with blood, and it was cast on the earth; and a third part of the earth was consumed, and a third part of the trees were consumed, and all the green grass was consumed.

Treasury of Scripture Knowledge

Summary

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.

Wormwood

Bible References

Wormwood

Hebrews 12:15
taking care that no one may come short of the grace of God, that no root of bitterness springing up may make trouble and by it many be defiled,