That is Michelangelo’s “Moses”, Moses as in the biblical figure, as in the basis for Charlton Heston—or is that the other way around. And those are indeed horns.
The idea of Moses having horns does come from the Bible…kinda. In the Book of Exodus, Moses is said to be “karan” in Hebrew. When St. Jerome translated the bible into Latin (what is now known as the Latin Vulgate, the bible used by the Roman Church), the word became “cornutam“, literally, “horned”.
The issue here is that the Hebrew, while it could be taken as “horns”, also suggests the word means the coned beams of light, rays, or even simply “shining”. Think about how we depict the sun’s rays as sort of cone-shaped beams, and we can maybe see how this ended up as “horned”. The irony is Jerome probably did not himself think of cornutos as “horned”, and likely correctly recognized the word as “shining” or similar (cornutos is, in other words, metaphorical). A somewhat more literal reading of the word and some poor understanding of the Hebrew original, however, and we now have a long tradition of “Horned Moses: Half-Goat, All Bad-ass” (coming to theaters, 2017).
Fast forward to Michelangelo, and you get his version of Moses, featuring the horns. All because an actually somewhat OK translation got interpreted somewhat oddly. History is all sorts of crazy.
For more information, here are two (academic) sources that might interest people.