To use this costume, simply put on the grey hooded robe. The glow - in - the - dark chest detail will start to shine in low - light conditions. For the best glow, expose it to bright light for a few minutes before entering a dark area. When it comes to storage, keep the costume in a cool, dry place to maintain its shape. Remember, this costume is for male children and is designed for Halloween fancy dress. Always follow the dry - clean - only washing instructions to keep the costume looking its best. Avoid rough play that could damage the glow - in - the - dark part. Have a great time wearing this spooky and unique costume!