Halloween costume help!!!

So I know it's August and Halloween isn't for another two months but I like to get started early and Halloween is my favorite holiday. I want to make a costume rather than buy one and since I'm really into makeup now, I want to be something/someone who looks fierce. I kind of want to dress up as Harley Quinn, but with Suicide Squad being out, there's going to be a lot of girls dressed like her. I can't think of anyone else to dress up as! Someone please help!