Barnacle
A small shelled creature fixed permanently to one surface — an attachment that, once made, does not leave.
A barnacle in a dream is the dream's image of an attachment that, once made, does not leave. The barnacle picks a surface as a larva and stays for life; the choice is made early and is not revisited. The dream brings the barnacle when something in your life — a loyalty made young, a habit attached to a particular place, a passenger you took on once and are still carrying — is a fixed feature that the host did not choose with full knowledge. A barnacle honoured as part of the ship is the dream affirming that the long attachment has become part of the vessel. A hull covered in barnacles to the point of slowing the ship is the dream noting that the permanent passengers have accumulated past what the ship was built to carry, and the journey is now slower because of who was let on.