I'm afraid to say that the story had many mistakes, but I liked the story. It was quite funny that it turned out to be his little brother or sister, and I liked the fact that he was running as he thought it was a monster that wanted to eat him. I liked it, but as I said before, there were far too many mistakes that I think you could sort out.
You repeated 'but adrenaline kept him going'. Instead of saying 'It', you put 'IT', which shouldn't have been there. When he got knocked over you added a '\' at the end of sentence. Also, try to avoid words that end with 'ly'. If you can change these around. I'll come back and review it. Keep writing.

My review has been submitted for consideration in "Good Deeds Get CASH!" .