Black slug looking thing?

[Mary Swims with Fish..]

Hello all, yes I'm new to salt water. I didn't realize there were so many hitch hikers. What in the world id this thing and does it need to come out?

 

[C. Eymann]

Scutus / black elephant limpet

 

[Mary Swims with Fish..]

Scutus / black elephant limpet

Is it okay or does it need to come out?

 

[C. Eymann]

Is it okay or does it need to come out?

Oh sorry, yea it's a good guy, harmless algea eater.

 

[RollaReefer]

Please could someone I'd this on my new coral please and is it harmful or need removing? Many thanks in advance and apologies for picture quality too