Revelation 8:11

And the star was called "Wormwood" [Note: The Greek word here means "bitter," See Lam. 3:15 ASV], and one third of the waters became wormwood [i.e., bitter], and many people died from the waters because they had become bitter.

Hebrews 12:15

Look carefully [at how you are living] so that no one falls away from God's unearned favor, and that no "poisonous plant sprouts up" to cause trouble and corrupt many people [Note: This is an analogy from Deut. 29:16-18 being used as a warning against the evil influence of wicked people],

Revelation 8:7

[When] the first trumpet sounded [I saw] hail and fire, mingled with blood, being hurled down onto the earth. And one third of it was burned up, and one third of the trees were burned up and all the green grass was [also] burned 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
Look carefully [at how you are living] so that no one falls away from God's unearned favor, and that no "poisonous plant sprouts up" to cause trouble and corrupt many people [Note: This is an analogy from Deut. 29:16-18 being used as a warning against the evil influence of wicked people],