Sub and Manta Ray

During the Cold War and probably now, there were submersibles that were intended to fall to the sea floor and drive around usually on tracks.

They were designed to be able to do work on the sea floor, usually tapping into undersea communication cables or cutting them in time of war.

This is the Hot Wheels Yellow Submarine from the Beatles movie of the same name.

Once repainted I think it will work as an interesting mini-submarine.

At the same time I got this giant manta ray.  As a kid I remember seeing them jumping in the Pacific Ocean off of Rainbow Pier in Long Beach, CA. 

These massive creatures would jump fully out of the water it was an amazing spectacle. 

 Here with a submarine.