Coral type id

[purplepolypeater]

What looks like an encrusting montipora yet has 1/4-1/2 inch tentacles at night. Was sold to me as a montipora but quite sure it's not. Can't seem to get a clear picture yet. Will try later just hoping for general ideas of similar species. Pretty sure it was wild. It looks like a browned out sunset montipora sort of with smaller polyps except at night they go crazy!