Pop culture unicorns have departed a lot from the myth, and the myth is one terrifyingly beautiful beast. These social creatures roam the lands to their hearts' content, exploring every nook and cranny, just like the Sagittarius sign. Unicorns are also deeply intuitive, understanding people and their intentions right away, and Sagittariuses have the same knack.
And unlike what My Little Pony would have you believe, being on the wrong side of a unicorn only has one ending - getting gored to death by their sharp horn. While Sagittariuses won't clobber you if you've upset them, they will tear your insides out with their cutting honesty.