From the provided pictures, I would lean the ID toward an M. doreensis hoping to find a sand bed to bury in.
If it is an M. doreensis, aka Long Tentacled Anemone, it will be happiest with the foot attached to a hard substrate under the sand. The sand should be deep enough to reach those little white spots, verrucae, on the column.
I personally don't like to have anemones that have not settled in hosting clowns.
Be prepared to feed it 3 times a week with meaty fish and shrimp based meals.
Best of luck LTAs can be very touchy during the first few weeks.