Sea grapes - Caulerpa racemosa

"Caulerpa racemosa" is a species of edible green alga, a seaweed in the family Caulerpaceae. It is commonly known as sea grapes and is found in many areas of shallow sea around the world. There are a number of different forms and varieties, and one that appeared in the Mediterranean Sea in 1990, which is giving cause for concern as an invasive species.