The ectoplasm-covered bedsheet is obtained from the innkeeper of Port Phasmatys during the Ghosts Ahoy quest to be given to Robin Hood in a nearby room. It is worn in the head slot. The bedsheet can be changed to a light green colour by covering it in ectoplasm.
When worn, the bedsheet makes the player resemble a classic "bedsheet" ghost. The bedsheet is not wearable in any other place than Port Phasmatys; attempting to do so will result in receiving a message, stating: "I'll only wear the bedsheet inside Port Phasmatys."
It is impossible to run, rest or charter a ship while you are carrying a bedsheet.