Single cell algal seaball (Codium pomoides)

On a broad sandy beach facing the Southern ocean this very firm, moist, velvety dark green ball was washed up with other ocean detritus. I have seen them before but never thought much about them. It was a bit larger than a golf ball, very slightly translucent, dense like it was full of water.
Apparently they can be up to 120mm diam. which is impressive for a single celled organism which can repair itself if damaged.
It appears fluffy underwater and feels velvety out of water due to hundreds of tiny hair-like filaments on its surface.