is it a clamp?

Dear Wetpixel members,

Can anyone please tell me what is this?

it keep moving, like a hand grapping something

very sensitive to movement. I need to move very carefully to get close to it.

very small, about 1cm only

Is this a clamp or just a plain coral (eating)

thx you

Andree

It's a barnacle, a crustacea usually described as a lazy because it lays on it's back & kicks food into it's mouth with it's legs. That grasping movement is the legs sweeping through the water & collecting food particles.