What is the name of sea creature with a pouch?

There are many sea creatures with pouches, so it's hard to give you a single answer! To help me narrow it down, could you tell me:

* What kind of pouch are you thinking of? Is it a pouch for carrying young (like a kangaroo)? A pouch for storing food (like a cheek pouch)? Or something else?

* What kind of sea creature are you interested in? Are you thinking of a fish, a mammal, a mollusk, or something else?

Once you give me some more information, I can help you find the name of the sea creature you're looking for!