Of all the costumes Harley Quinn has had, her latest is a knock-out that belongs in her top looks thanks to Black Adam. Try these amazing literary Halloween costumes, these superhero costumes for kids and toddlers, womens movie costumes or check out this Rioter’s guide to making your own Squirrel Girl costume. It’s fitting for the character as well, his iron jaws strong enough to chew straight through steel, let alone cement.