concept Art: Trick of Treat

This is the Halloween special for Conceptart.org's "Creature of the week". I gave it a shot. I think I could've done better, but I have been frustrated with my art for the past couple of days. Specifically I have had a lot of trouble with digital painting. Usually this frustrations happens when I am about to make a leap in art, or have reached a plateau and am remaining steady stylistically. Hope it is the first of those two. Anyway with no further adu, here is my piece: