Atlantic slipper shell

The Atlantic slipper shell, scientifically known as Crepidula fornicata, is a marine snail belonging to the family Calyptraeidae. These snails are characterized by a humped or flattened shell with a unique decklike partition inside. They are found worldwide in shallow waters, often attaching themselves to rocks or living within the empty shells of other mollusks.1

A notable aspect of their life cycle is sequential hermaphroditism: they begin as males and later transform into females. Fertilization is internal, and females release thousands of microscopic larvae that disperse before settling on the ocean floor. The Atlantic slipper shell, in particular, is about 1.5 inches long and has been introduced to various regions, where it can become a nuisance in oyster beds.1