A tan turban, adjustable to fit creatures from Halfling to Ogre size. When the user is ready to sleep, the user rubs at the upper area of the turban with a finger until touching on the sleeping imp in the turban. The imp wakes, and the turban wearer immediately lapses into peaceful, silent sleep.
The imp watches over the sleeper, perched on the turban. The imp decides whether or not to wake the sleeper. If the imp does not wake the sleeper, then the sleeper is impossible to wake. If the imp decides to wake the sleeper, the imp dives back into the turban and the sleeper immediately wakes, clear-eyed and alert.
The imp has an Armor Class of 0, and 10 hit points. It will not fight, speak, or leave the turban. If threatened credibly, it will always wake its sleeper. If somehow the turban is separated from the sleeper during sleep or the imp is killed, a Cure Disease spell can wake the sleeper (who will have nightmares for a year and a day, robbing 2 hours of sleep per night.)
Four hours of sleep with the turban count as eight hours of normal sleep.
Magic Users and Clerics value this object, because it can protect them from being woken by random encounters or wandering monsters during their precious resting time—if their comrades can handle the menace, then they can best serve their group by completing their rest.