The wolf looked kinda cute
I really liked the dramatic music, the animation started out nice, but when the flying wolf appeared, he didn't look menacing enough. In fact, he looked more like a stuffed animal. A few too many curves.
The first problem has to do with composition. The creature was a bit too centered on the moon. And you drew strong curves in the wings and a loopy curve for the jaw--which kinda looked whimsicle to me. But one of the points I'm trying to make is that all the wolf should contrast the round moon behind him, to make things more unsettling.
The other point is that making everything more asymmetrical will add to the uneasiness as a whole.
Also, adding shadow would help.
And he didn't move--the second problem. What I would do to make it dramatic is make him throw his head back into a howl, then pan out as he unfurls his wings, then at the very end, after the music stops, show a close-up of just his eyes, maybe with a low growling sound.
I'm guessing that the birthday present is bringing life to that wolf character or something like that.