You will get problems, if its look is very close to that of the movie.
You like it because of it uniqueness, if you re-use it, its uniqueness is gone.

I can understand that you can sort of "fell in love" with certain characters and certain designs, but you shouldn't copy it. There is a huge amount of different dragons, why not choosing two or three of them and combining them.
Or, if you are skilled in drawing, draw a dragon from your mind, let your pencil surprise you with discoveries of dragons that never had been seen before! ;-)