Think he'll ever do that again? Neigh.

Let's interpret the body language:

Ears back: fuck off right now. One back, one forward: approach with caution. Ears forward: should be okay.

The ears pinned back are a sign of anger. Also narrowed eyes. Don't provoke!

As a horse caretaker, that horse was warning him to back off long before it actually bit him.

OMG PWNIES!!!

Was that a unicorn running away after the bite?

Yes! Let's see a close-up of that:

Breaking news: Sarah Jessica Parker attacks paparazzi.

That's not funny.