Revelation 9:19

for the power of these horses is in their mouths, and in their tails: for their tails were like serpents, and had heads, with which they do mischief.

Ephesians 4:14

that we should be no longer children, fluctuating, and carried about with every empty doctrine, by men vers'd in sleight and the crafty arts of deceit:

Revelation 9:10

they had stings in their tails like scorpions; and they had leave to molest men for five months with their stings.

Treasury of Scripture Knowledge

Summary

For their power is in their mouth, and in their tails: for their tails were like unto serpents, and had heads, and with them they do hurt.

Bible References

In their tails

Revelation 9:10
they had stings in their tails like scorpions; and they had leave to molest men for five months with their stings.
Ephesians 4:14
that we should be no longer children, fluctuating, and carried about with every empty doctrine, by men vers'd in sleight and the crafty arts of deceit: