"Then out of the smoke came locusts upon
the earth, and power was given them, as the
scorpions of the earth have power. They were
told not to hurt the grass of the earth, nor any
green thing, nor any tree, but only the men
who do not have the seal of God on their
foreheads."
Revelation 9:3-4

They tormented men without God's mark on
their foreheads. Their sting brought terrible
pain.