Online shopping from a great selection at Clothing, Shoes & Jewelry Store. Cause a splash at your next party when you arrive in one of our mermaid costumes purchased at a Little Mermaid Costumes Emerald Mermaid Adult Costume . OMG - This is the best costume I have ever bought. I cannot wait until this weekend! I hate the plastic, cheap costumes you find everywhere. This one is amazing/5(24).