If I had Written a YA Horror Novella...

If I had written a YA horror novella it probably would have been very much like J A Norton's 'Deliver us from Evil', and I highly recommend it to any of your younger siblings (or indeed you if you enjoy high-adventure, horror, fantasy and action).  Norton has made the novella (about 40K words) available as an eBook on Amazon, Smashwords etc. Take a look if you're looking to purchase a gift for kids over 13+

http://www.amazon.co.uk/Deliver-Us-From-Evil-ebook/dp/B006C752U8/ref=pd_rhf_gw_p_t_2