Some people would call this a Kirin, which in modern usage is depicted as a dragon-like Japanese unicorn. However, they traditionally were more like dragon-deer, and were considered completely different entities from unicorns. This beastie actually has more in common with the Chinese Sin-you, which was more lion-like, but had the single unicorn horn. In both cases, they enjoy showing up at courtrooms, where they free the innocent and slay the guilty.
They're also pretty effective against schoolyard bullies.
