Can someone tell me about the Babadook movie?

I always pass by it when I'm scrolling through Netflix. And as curious as I am about it, I'm also pretty scared to see it. It looks like a great horror movie I'd probably would end up watching. But the actual Babadook villain looks really frightening. Why would a villain like that wear a fancy top hat like a fancy rich man? Why would a creepy creature like slenderman wear a regular smart looking suit and tie like a businessman? It reminds me of one of the creepypasta characters that I'm afraid to look at for least than 5 seconds. (It doesn't remind me of slenderman. I've been wanting to see that new slenderman movie for a while so I'm good with him) So I don't wanna watch it and at the same time I do wanna watch it. Just wanna know how scary is it? What's it about?