Dress up your toddler in adorable style for Halloween with the Toddler Monarch Butterfly Halloween Costume Dress with Headpiece from Hyde and EEK! Boutique . This monarch butterfly Halloween costume dress is designed in yellow and black hues in a full length for a cute look. The included black headpiece adds a perfect finish, and it's made with soft and lightweight fabric for reliable comfort. Boutique : Thrilling delights. Curious oddities.