Revelation 17:7, 12

But the angel said to me, “Why do you wonder? I will explain to you the mystery of the woman and of the beast that carries her, which has the seven heads and ten horns.

The ten horns that you saw are ten kings who have not yet received a kingdom, but [together] they receive authority as kings for a single hour [for a common purpose] along with the beast. [Dan 7:20-24]