The term 'Marine Hitchhiker' refers to a type of fish known as a remora, which is a six-letter word. Remoras are small, slim fish that have an adhesive disc on their heads, allowing them to attach themselves to larger marine animals such as sharks, whales, and turtles. They feed on the scraps of food left behind by their hosts, and are sometimes referred to as 'suckerfish' or 'shark suckers'. Remoras are found in tropical and subtropical waters around the world, and are an important part of the ocean's ecosystem.