Suspected Starfish - Any thoughts?

[RummynoseToReef]

This guy just appeared from underneath some live rock in my tank. The setup is only ~4 months old, so there's still a lot of life showing up. Any reason I should be concerned about it?

Thanks!

 

[Steve and his Animals]

Not a sea star, looks like a sponge that's growing along the groove in the rock. Harmless.

 

[Duffer]

if you are talking about the White object, that is most likely sponge...not a starfish