Amulet of restful sleep
There is a 13.5% chance that a randomly-generated amulet will be an amulet of restful sleep. The amulet is generated cursed 90.5% of the time, uncursed 9% of the time, and blessed 0.5% of the time.
Wearing the amulet of restful sleep confers the restful sleep property as an extrinsic: you will fall asleep sometime within 100 turns of wearing the amulet, awakening within 1 to 20 turns or when disturbed; this cycle continues as long as you have the amulet worn. Sleep resistance will not cure the condition, but prevents you from actually falling asleep. Eating the amulet can confer intrinsic restful sleep, causing you to randomly fall asleep with the same effects.
The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.While you have restful sleep and are asleep, you regenerate hit points in a manner similar to regeneration, at the rate of 1 additional point per turn. If you are not polymorphed into another form, the healing from this stacks with normal HP regeneration and any additional regeneration properties (e.g. from a ring of regeneration). It does not cause you to hunger any faster than normal.
The amulet of restful sleep is one of many reasons to avoid wearing unidentified amulets early on: you are likely to fall asleep with hostile monsters around, and may die before you are disturbed from your sleep enough to awaken.
With that in mind, the amulet of restful sleep is fairly easy to test for: if you notice yourself falling asleep while wearing an unknown amulet, and it wasn't caused by a monster's sleep attack or a sleeping gas trap, then the amulet is restful sleep. Conversely, if you haven't fallen asleep within 100 turns and don't have sleep resistance, it is guaranteed to be something else. Once identified, the amulet is best saved for polypiling into something more viable to wear.
The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.With enhanced regeneration, this amulet becomes situationally useful - uncontrolled sleep should still be avoided, and most players will want to have sleep resistance anyway, which will negate its effects. One example of potential use is for a player barricading themselves in a safe location (e.g. a closet or empty locked room on the other side of a staircase from monsters) and putting it on to take advantage of its enhanced regeneration while they fall asleep. Engraving a (semi-)permanent Elbereth on the desired square prior to donning the amulet is advisable in case a hostile phasing monster or giant approaches their location.
The amulet of restful sleep first appears in NetHack 3.0.0.
In SLASH'EM, putting on a blessed amulet of restful sleep will put you to sleep immediately, allowing you to specify for how long (up to 500 turns); the sleep cycle will then continue as in vanilla NetHack. Sleeping slows down nutrition burn as well in SLASH'EM, giving the amulet some marginal use if you don't have a ring of slow digestion.