The term 'Hitchhiker on a Shark' refers to the remora, a type of fish that attaches itself to larger sea creatures such as sharks and whales. The remora has a specialized organ on its head that allows it to attach itself to the skin of its host. It feeds off of the scraps of food left by the host, and in some cases, it can even provide protection for the host from predators. The word remora is derived from the Latin word for 'DELAY, ' which is fitting since the remora often delays the progress of its host.