sea walnut

Mnemiopsis leidyi (Sea Walnut):

Mnemiopsis have a lobed body that is oval-shaped and transparent, with four rows of ciliated combs that run along the body vertically and glow blue-green when disturbed. They have several feeding tentacles. Unlike cnidarians, Mnemiopsis doesn’t sting. 

These little guys are found around the beaches in my area. They fit in the palm of your hand. :)