In the level "The Storm", you must watch a saved film and go until the point where you fight the Scarab, and go into the large wrecked boat. In the bridge of the ship, there is a poster displaying a man wearing a big pirate hat, with the words "Sheik of the Ship" below it.

This is a reference to "Pimps at Sea", a long time joke by bungie, commonly an april fools joke.