Oh! This is a great example of a bamboo whip coral.
This one is probably a few meters tall.
Taller than D2.
Bamboo coral comes in a number of different forms.
You'll see it like this, as a long unbranched whip.
Sometimes you see them in fan shapes.
All these different shapes can be very useful.
Having such a long whip-like body is very important in this environment
because it allows this coral to move in the current in any direction.
It gives it a lot of range of motion and also gets the polyps up off the seafloor.
So all these different animals that filter-feed in the deep sea have
come up with different solutions to the problem of how do we get food to our mouths.