Question about Rihanna's song Rockstar 101. Is there some evil in there or is that just me?

I saw the video a few days ago, and the part that got me was when she was dancing around in a horned hat in a circle painted on the floor. If that dosent say wierd, i dont know what does. Can anyone else shed some light on this part of her video? What is it for? Why did she do it? Is it just a harmless dance in a regular video? And where is the young rihanna with her long pretty hair and non-emo looks?