The Rakshasas women give birth on the very day they conceive; they are capable of assuming any form at will and they change their forms (at will).
सद्यो हि गर्भान् राक्षस्यो लभन्ते प्रसवन्ति च। कामरूपधराश्चैव भवन्ति बहुरूपिकाः॥