Never heard that, at most: how the hell have you looked to “that” and realised that it would be an interesting shot.

If someone managed to 3D print a thing that big, it would be known just for that.

Probe lens or periprobe lens?

Not exactly the most inexpensive option but it’s cheaper than a custom built aquarium and diving there with an underwater camera.

Lens size + sensor size.

It’s like trying to fit an entire high school inside a van for a field trip, they won’t fit (unless you make something similar to a milkshake for better space management but then the parents might be slightly upset).

But if you do that (it’s totally understandable) take a quiet one that doesn’t disturb the photoshoot.