It's true. Moses used to have horns. Sort of.
In the early 5th Century, when Jerome translated the Latin Vulgate, he misinterpreted the story of Moses' encounters with God at Mt. Sinai.
Exodus 34:29-35 describes Moses as having a supernatural radiance to his face after each encounter with God. The effect was so striking that it frightened the Israelites and he donned a veil to hide his face from them.1
When Jerome translated this passage into Latin the part about Moses' face being radiant, or emanating rays of light was mistranslated as him having "protruding horns".
"Radiance emanating from his face" became "horns protruding from his head".
Artists of the time seized on this esoteric idea and all depictions of Moses from this period show him sporting little goat-like horns.
Long after this mistake had been accounted for, artists persisted in using the horns to depict Moses because it served as such an iconic device for identifying him. The most famous example being Michaelangelo's sculpture created for the tomb of Pope Julius II.
So for a time, Moses had horns.
It would seem that in our fallen state we are not prepared for even a reflection of God's true glory.↩