Turtle (Submersible) (en.wikipedia.org)

The title of this submission, reminds me of certain animal, which is very unknown, said animal has a shell, better check it out yourself, https://en.wikipedia.org/wiki/Turtle

> The shape of the hull, Gale informed Silas Deane, "has the nearest resemblance to the two upper shells of a Tortoise joined together."

> Named for its shape, Turtle resembled a large clam as much as a turtle

Come on, it looks like a goddamn acorn. It's even made of oak.