Just posted in the hitchhiker ID forum. Someone else also thinks it's a type of asterina. I'm reluctant to keep it, but I'm also kind of intrigued because it looks nothing like the typical small and white asterinas. Makes me want to keep it but this is my main display tank and slowly adding more corals. I'd hate to see this turn into an uncontrollable population and then see corals getting chomped on. Not sure what to do.Looks to be one of the Asterina stars. Some eat co als, some eat algae. I've got one that's almost an inch and a half across.