If you dive much beyond 30m here in Tas, s(hallower in the darker areas such as the Huon River and D'Entrecastaux Channel,) you see theses trange beasties called Sea Whips. Indeed one site in the D'Encx Channel is known as "Mike's Hairy Bottom", they are so profuse.
Here's some video taken last year on a dive off the southern end of Maria Island.
Now I know they are animals of some sort, maybe related to corals but does anyone have any idea of what they actually are? They are just like a horse whip and are sort of hard and leathery to touch.