Awesome. You've got this totally creepy, scary looking monster--and he's just walking past the viewer, tipping his hat. A rather ominous gesture--it seems like he's saying "I'll be seeing YOU later!" I absolutely love it.
However, the contrast between him and the moon is really dramatic--but it makes it hard to see the details of the edges of the picture. Like his hat and arms--they blend into the blue. So I would suggest either lightening the blue, or perhaps lightening the very edges of his hat to make it stick out more.
I really love the details in his costume--the patch on the hat is an EXCELLENT touch. His empty, savagely wild eye coupled with the gentlemanly expression of tipping a hat is truly a remarkable, original and highly creative idea!
Makes me think of a mix of the big bad wolf and the wicked witch. So evil, and yet polite :)