Six is good. If we are going for a horror show kind of feel, it should be about a minute long process of them going from crazy adorable, blood and fluff covered children, to a crazy description of their transformation.
For your character, I'm thinking a combination of a deep sea angler fish and a leaf nosed bat. The size of your monster is up to you.
I'm thinking the skin should be that of the Angler fish, rough and slimy, a crazy long under bite with long sharp fangs hanging from each way, large black eyes, thick short feelers that run all over his body except for his large bat like wings, two small claws for arms, long strong legs with three sharp claws for toes, an almost fin like look for his massive tail. Large pointed ears.
How is that..?