That's a mole cowrie or chocolate banded cowrie (Talparia talpa), a type of large sea snail that live on coral reefs off the coasts of eastern Africa, South and Southeast Asia, Polynesia and western Australia.The black outer layer is the cowrie's mantle, which cover and hide the inner shell. When the mantle opens, it reveals that banded shell that looks like a portal into another dimension!Image: <a href="https://twitter.com/seastung/status/1143837301916807168">@seastung/Twitter</a>​#cowrie #molecowrie #cowry #seasnail #marinelife #marinebiology

Mole cowrie (Talparia talpa) in Mactan Cebu, Philippines by <a href="https://commons.wikimedia.org/wiki/File:Cypraea_talpa_(alive).jpg" class="on">Juuyoh TANAKA/Wikimedia Commons</a>​