The subject was "fear" and it's my interpretation of such feeling. Being bound, while screaming, feeling pain of being, unable to do antything at the same time. Being honest it refers to my fear of duties and how I will fail on them. Though it may have many other interpretations.
First of all... If You love horses, You'll hate this :P Second thing... I don't like horses When I was in my primary school I started to draw creatures like this... I wanted to draw it in other way but... damn