Prove that these sea creatures do exist with the Magical Mermaid Costume for Girls. Take the mermaid out of the ocean for the Halloween season so that your daughter can feel like a real star. This outfit features a blue floor length dress. The dress has designs of seaweed, coral, and more on it that give it a truly aquatic feel. The sleeves of the dress drape off the arms and are of a sheer material. The bottom of the dress features the dress breaking off into a fin just like a mermaid has. This oceanic dress is going to really make your daughter feel like one of these beloved mythical creatures. Mermaids are an extremely cute and easy costume to pull off on Halloween.