Quite beautiful and IMO should be left in the ocean.
The GREAT majority will starve to death in a reef tank. Quite irresponsible of a store to be offering these for sale imo...
Basket stars or feather stars.
They live on the reef hiding by day and come out at night and unfold into a huge web of tentacles a couple of feet in diameter which catches Zoo plankton passing by in the water column.
Reef tanks would have problems keeping up this kind of nutrient load.