Clearly the place to be on Saturday night was at Heidi and Seal's 10th annual Halloween bash in LA. Just like you and me, the stars went all out with their costumes. Despite being told by star stylists that sexy is out, Rihanna and Selita Ebanks looked va-va-voom. Heidi and Seal outdid themselves by dressing up as crows — freaky! And Agyness Deyn and Alexa Chung's duo getup made me crack up. Can you guess who this flashy mermaid — or shall I say merman — is? Click through to find out and to see more stars in their costumes.