Mermaids are half fish, half human sea creatures that make the depths of the ocean more enchanting, but who would want to be a mermaid when they could be an alluring, conniving, much smarter sea creature? A caecilia is a half human, half octopus, and that's what one of the most iconic Disney villainesses is. You can become Ursula from Disney's The Little Mermaid this Halloween and look sexier than any mermaid in the sea. This form-fitting dress is in a matte black with purple lace embellishments, and a green gem in the center of the violet neckline. The bottom of this dress is adorned with plush tentacles that are a black velvet on the top and a deep, sequin-laden purple on the underside. Top off your wonderfully evil look with a pair of black pumps, elegant gloves, and a white wig.