Revelation 8:11

And the name of the star is called Apsinth. And the third part of the waters became apsinth; and many of the men died from the waters, because they were bitter.

Hebrews 12:15

looking diligently lest any one may fail from the grace of God; lest any root of bitterness springing up may trouble you, and through it many may be defiled;

Revelation 8:7

And the first sounded, and there were hail and fire mingled with blood, and cast to the earth: and the third of the earth was burnt up, and the third of the trees was burnt up, and all green grass was burnt up.

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
looking diligently lest any one may fail from the grace of God; lest any root of bitterness springing up may trouble you, and through it many may be defiled;