Revelation 9:12

They had breastplates like breastplates of iron. The sound of their wings was like the sound of many chariots and horses rushing to war.

They have tails like those of scorpions, with stingers. In their tails they have power to harm men for five months.

They have over them as king the angel of the abyss. His name in Hebrew is “Abaddon”, but in Greek, he has the name “Apollyon”.

The sixth angel sounded. I heard a voice from the horns of the golden altar which is before God,

saying to the sixth angel who had the trumpet, “Free the four angels who are bound at the great river Euphrates!”

The four angels were freed who had been prepared for that hour and day and month and year, so that they might kill one third of mankind.