The power of being yourself and the strength doing what you want. The dream shows that you have an ability to feel yourself and do whatever you like to do in your life. You are the person who is confident enough to be himself instead of pretending someone else. If you are dreaming that you are invincible in front of bad people, it means that you do not care about others opinions and do not let to control your life.
Dream dictionary: Invincibility dream meanings
…(Distinguished) In a dream, a horn means strength and invincibility. Having a horn in a dream means conquering one’s enemy. If one sees a ruler having two horns in a dream, it means that such a ruler will control interests throughout the East and the West. A horn in a dream also represents a relative from whom one can draw benefits. If one grows two animal horns in a dream, it means that he will die from grief and coercion. A horn in a dream also represents a century, years, weapons, money, children, or the reason behind one’s pride or his distinguished look. (Also see Trumpet)…