Apparently Veracity mentioned that it has no way to obtain it right now, Yes i'm aware of that quest with the Great Demon Baphomet but some NPCs are missing(or maybe i just missed it when trying to scout it) so i can't really tell, Plus its only the def one. It's better to have maybe a custom quests for this 2 horns.
And about it's effect i'll go by just +100 ATK and its demi-human effect. In my opinion adding an anti freeze effect to it is already OP so i won't support that.
Hope more people with share their ideas on its effect and also on how to acquire the item thanks.