Sponge Ciolcalypta Sp.

These tubes are soft and flexible and come up from a solid mass just under the sand.  As it doesn't move when poked, it's probably a sponge rather than an ascidian.

The MLSSA site has a similar picture identified as Ciolcalypta Sp and titled Demospongiae

Approx. 2 cm high; Aldinga Dropoff SA