Polymorph control

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Polymorph control is a property in NetHack that allows the hero to maintain control over the form they take whenever they polymorph.

The only source of the property is wearing or eating the ring of polymorph control.

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that the information below is still accurate, then update the page to incorporate it.

Per commit 486ed290, blessed potions of polymorph grant a controlled polymorph when quaffed.

Description

If the hero polymorphs while they have polymorph control, and is not stunned or unconscious, a prompt will appear asking what type of monster they want to become: once you type the name of that monster and confirm, the hero will attempt to polymorph into that monster. This will always prevent system shock from occurring, and allows a form to be chosen even in special cases where the hero would otherwise become a predetermined target (i.e. polymorphing while wearing dragon scales or a dragon scale mail, or else polymorphing while you are a vampire or werecreature).

If the hero has lycanthropy or are in vampire form, and a transformation is triggered by means outside of polymorph magic (such as the random chance per turn or unholy water for lycanthropy, or the #monster extended command for vampire forms), a prompt is instead generated asking whether or not you want to shift from the hero's current form, and declining will not transform them.

Choosing to polymorph into a monster of the hero's own species will cause random adjustments to their attributes and experience level, while polymorphing into the hero's own species while in the form of another monster will return them to their base form, with both transformations printing the same messages. There is also a ¹⁄₅ chance that a polymorph will cause the hero to turn into their own species regardless of if they have polymorph control.

Strategy

There are many reasons for a player to want control over their polymorphs, whether it is gaining advantages and special abilities in combat, obtaining otherwise-rare pets, obtain hard-to-get intrinsics, or even making travel less of a hassle.

Advantage in combat

Polyself has vastly improved the record for game-time speed ascensions. Some species have higher speed that lets you move, attack and react faster to enemies—in short, deal more damage per turn. Some species also have multiple or additional attacks, dealing extra damage. Whenever you attempt to hit a monster, you use all of your form's attacks. If the monster has no weapon attacks but can wield a weapon, you typically get your weapon damage added to the first attack (which may be a claw move); if a monster has multiple weapon attacks, you hit with your weapon multiple times. High-level monsters often have a lower base AC, effectively giving you an AC bonus if you turn into one. If killed by HP loss while polymorphed, reverting to original form is a "free" amulet of life saving.

Possible choices include:

• Master mind flayers have 0 base AC and can fly. They have five brain-sucking attacks; each one causes d10 damage to monsters with brains. This is one of the best forms to rack up damage in melee, and they can wear a cloak or armor for magic cancellation. However, mind flayer attacks also have some dangers:
  • Accidentally attacking/bumping a cockatrice is a common stoning instadeath when in the form of a mind flayer: the mind flayer's tentacles are bare skin, and no armor can cover them. Similarly, eating Medusa's brain will result in delayed stoning, while eating any Rider's brain will kill you instantly.
  • The brain-sucking attack adds nutrition on each hit, making it possible to become oversatiated very quickly - this results in frequent dexterity abuse and also puts you at the risk of instadeath by choking if you eat any comestible while oversatiated, including wraith corpses. Choking and dying will not revert you to original form - among other things, this means that curing delayed stoning in this state (e.g. eating a cockatrice egg) will require non-comestible means, such as a potion of acid or polymorphing into a form with stoning resistance.
  • If polymorphing into a (master) mind flayer as a human, eating the brains of soldiers counts as cannibalism, hurting your Luck and making any subsequent Luck-reliant actions riskier.
• Jabberwocks likely deal the most damage per turn of all polyforms (without an enchanted artifact weapon), can wield weapons, and are capable of flight. However, they can only wear non-body armor and cannot cast spells.
• Minotaurs are a good compromise between speed and damage output.
• Titans can fly, have base AC −3, and are faster than the other recommendations. They can also pick up boulders, and cannot be engulfed.
• Elvenkings are speed 12, base AC 10 (same as you) and HD 9. They allow you to hit with your weapon damage twice per move, with a 2d4 bonus to each attack. Note, however, that elven characters cannot use this form.
• Vampire lords are speed 14 with base AC 0 and HD 12. They regenerate and are unbreathing. This allows you to swim, and you cannot choke to death from wraith corpses (e.g. when oversatiated due to brain-eating in mmf form). Both V can see any @ on the same level as you, as if telepathic, without needing to be blind. Useful for finding shops and temples. Note however that V are silver-hating, and cannot wield silver sabers. (They can however throw silver daggers.) Before polymorphing to a V, check that rings of polymorph control don't happen to be silver rings.

Out of the above monsters, only Elvenkings, master mind flayers and vampire lords are medium-sized, and thus can wear all forms of armor. Jabberwocks and minotaurs are large, and titans are huge, so they cannot wear torso armor. They cannot benefit from the extra AC of that armor, nor from the magic resistance, reflection or magic cancellation they provide.

Pay attention to the base level of the species, as this determines your resulting HP. If it is not enough to survive combat, you may need to increase it. This is only worthwhile if you plan to be unchanging, as the increase is lost when you transform back. You also regenerate HP at the same rate as your species, so having regeneration or healing magic is useful.

Be careful when using a form that has a contact attack. Attacking a footrice will cause stoning and biting a green slime causes sliming. Forms with many such attacks, such as mind flayers, may also suffer multiple splashes of acid when attacking jellies. If reaching the Astral Plane in changed form, attacking any Rider as a mind flayer will prove to be fatal, as a tentacle hit counts as eating the corpse.

Special abilities

When polymorphed into certain species, you can use their abilities with the #monster command:

• A dragon's breath. The black dragon's disintegration beam is a particular favorite, since few monsters are disintegration-resistant. For example, a monk can defeat Master Kaen by flying over lava and breathing a blast of disintegration at him.
• A gremlin's ability to split near a source of water. This results in tame gremlins.
• A mind flayer's psychic blast, which wakes nearby monsters and can hurt them. Some players use this to wake inaccessible enemies such as the Master Assassin or the Wizard of Yendor.

Laying eggs

Female characters who polymorph into oviparous monsters can use the #sit command to lay eggs, which hatch into pets of the same species. This can be used to gain pets of powerful species, such as dragons and purple worms, although they usually hatch into baby forms that take a while to grow up.

You can then kill the dragons after they grow up and take their scales. However, dragons only leave their scales ¹⁄₃ of the time.

Another tactic is to lay cockatrice eggs and use them later to petrify enemies. Note that your Luck is penalized by −1 each time you break your own eggs, to a maximum of −5.

Gaining intrinsics

Most of your attributes are reset when you return to original form, but you keep any intrinsics gained while in monster form. For example, if you eat poisonous corpses that damage your strength, you may gain poison resistance and still keep your original strength when you change back.

Another way to gain intrinsics is to polymorph into a metallivore or gelatinous cube and eat rings and amulets. This way, you do not have to wear those items to enjoy their benefits. Note that some items cannot be eaten, some intrinsics cannot ever be gained, and some items have unwanted side effects. For example, the intrinsic from a ring of regeneration will also cause you to burn nutrition faster, even when your HP is full. Interestingly, it is possible to get both intrinsic polymorphitis and polymorph control from rings, allowing you to polymorph from time to time like a shapeshifter monster.

Polymorph control is also useful for temporary intrinsics and other properties, such as a silver dragon form to deal with a Gnome With the Wand of Death, or a winged gargoyle form to pick up a cockatrice corpse without gloves - one common such use is the xorn form's phasing ability to move more efficiently on non-teleport levels, e.g. to get the Castle's wand of wishing without having to fight the army inside. Other similar uses include turning into a nymph to steal items from other monsters, becoming a cockatrice to petrify monsters, or turning into a major demon to summon tame demons as you attack enemies bare-handed.

Other uses

Some players turn into an air elemental to travel, especially on the hectic Elemental Planes. Their base speed is 36, the highest of all monsters, and is further increased if the player has extra speed. They are permanently blind and cannot wear armor or use most items, so this strategy requires care. It is frequently used by players attempting speed ascensions.

Turning into a pudding and then getting yourself split by an enemy's iron weapon will create a tame pudding. You can then strike it until it turns against you and then commence pudding farming.

A mountain centaur is the fastest form that can operate a pick-axe, e.g. in the dig for victory phase of a speed run.

Good choices for self-polymorph

Having a ring of polymorph and a ring of polymorph control allows a low level character to become more powerful. Good options for polymorphing include:

Hit dice	Armor class
greater than 14 = Excellent 12 to 14 = Very good 9 to 11 = Good 7 to 8 = Mediocre 5 to 6 = Poor 1 to 4 = Very poor	less than −3 = Excellent −3 to −2 Very good −1 to 0 Good 1 to 3 Mediocre 4 to 6 Poor 7 to 10 Very poor

Creatures which can wear all armor

Creature	Pros and cons
A Aleax	+ Good attacks (W1d6+W1d6+1d4). + Good hit dice (10). + Good base armor class (0). + Cold, shock, sleep, and poison resistant; see invisible. − Slow (8).
g gargoyle	+ Stoning resistant; if you are turning to stone, polymorphing into a gargoyle will stop the stiffening process. Also useful for safely killing cockatrices. + Good attacks (2d6+2d6+2d4). + Excellent base armor class (−4). + Strength 18/**. + Doesn't breathe or eat. − Poor hit dice (6). − Slower than normal speed (10)
h master mind flayer	+ Brain sucking does excellent (5d10) damage against monsters with brains. Beware of monsters with helmets! + Gain nutrition without risk of choking when sucking brains + Very good hit dice (13). + Good base armor class (0). + Can fly. − Comparatively weak attack against non-brained monsters (1d8), although you can wield a weapon − Can't safely attack cockatrices or green slimes. − Often an early genocide choice. − Risk of cannibalism by sucking the brains of your original race. − Usually fully satiated by sucking brains and will not be able to eat a lizard if delayed stoning has begun.
L lich, L demilich, L master lich, L arch-lich	+ Good attacks (1d10C+M0d0m, 3d4C+M0d0m, 3d6C+M0d0m, 5d6C+M0d0m). + Good, very good and excellent hit dice (11, 14, 17, 25). + Good, very good and excellent base armor class (0, −2, −4, −6). + Cold, sleep, poison resistant; master lich is fire resistant; arch-lich is fire and shock resistant. + Doesn't breathe, doesn't eat, undead, regenerates. − Often an early genocide choice. − Slow.
V vampire, V vampire lord	+ Will drain levels from most other monsters. + Good and very good hit dice (10, 12). + Mediocre and good base armor class (1, 0). + Sleep and poison resistant. + Fast, strength 18/**. + Doesn't breathe, doesn't eat, undead, regenerates. + Can fly. − Can't safely attack cockatrices. − Vulnerable to silver.
n wood nymph, n water nymph, n mountain nymph	+ Can steal objects from other monsters. + Can remove an iron ball and chain. + Can teleport. + Doesn't eat. + Water nymph can swim. − Very poor hit dice (3) and base armor class (9).
& succubus, & incubus	+ Can steal objects from other monsters. + Good base armor class (0). + Doesn't eat. + Can fly. + Fire and poison resistant. − Poor hit dice (6). − Can't safely attack cockatrices.
Z skeleton	+ Very good hit dice (12). + Strength 18/**. + Cold, sleep, poison, and stone resistant; doesn't breathe. − Poor base armor class (4). − Slow (speed 8).

Creatures which cannot wear all armor

Creature	Pros and cons
g winged gargoyle	+ Stoning resistant; if you are turning to stone, polymorphing into a gargoyle will stop the stiffening process. Also useful for safely killing cockatrices. + Very good attacks (3d6+3d6+3d4). + Good hit dice (9). + Very Good armor class (−2). + Fast (15), strength 18/**. + Can wear helm and boots. + Doesn't breathe or eat. + Winged gargoyle can fly and lay eggs (although these mostly hatch into regular gargoyles). − You will break your shirt, body armor, and cloak
Adult dragons (various)	Black dragons have a powerful disintegration breath attack which can instantly kill any foe, including extremely tough baddies such as Master Kaen and Demogorgon. Silver dragon is arguably the best general-purpose fighting dragon form due to its intrinsic reflection. Gray dragons have magic resistance, but the benefits are lessened since polymorph traps are no longer a dangerous threat (due to you having polymorph control). It is possible albeit difficult to create silver or gray dragon scale mail by polymorphing into one of these forms. Unless you are a female character initially, you'll have to polymorph repeatedly until you turn into a female form of the dragon, and then #sit to produce eggs. Raise the pet baby dragons until they turn into adults, and then have them killed. They might leave dragon scales, which can be turned into dragon scale mail using a scroll of enchant armor. If you lack poison resistance, you can easily gain it by polymorphing into a green dragon and eating poisonous corpses. Although the green dragon is poison resistant, you can still permanently gain the intrinsic by eating poisonous corpses ("You feel especially healthy"). If already wearing dragon scales or mail, you become that dragon. + Good attacks (B+3d8+1d4+1d4). + Excellent hit dice (15). + Good armor class (−1). + Has an intrinsic depending on the color. + Can fly. + Strength 18/**. + Can lay eggs (if female) to produce good pets. + Breath weapon. − Cannot wear any armor nor wield any weapon. − You will break your shirt, body armor (except dragon scales), and cloak. − Can't safely attack cockatrices (except yellow dragons which are resistant to stoning).
H titan	+ Good attacks (W2d8+M0d0) + Very fast. + Excellent hit dice (16). + Very good armor class (−3). + Strength 18/**. + Being huge, cannot be engulfed (important on the Astral Plane) − You will break your shirt, body armor, and cloak.
J jabberwock	+ Excellent attacks (2d10+2d10+2d10+2d10). + Excellent hit dice (15). + Very good armor class (−2). + Can fly. + Strength 18/**. + Can wear boots, shield, and helm. − You will break your shirt, body armor, and cloak. − Can't safely attack cockatrices.
& marilith	+ Excellent attacks with weapons (W2d4+W2d4) plus claws (2d4+2d4+2d4+2d4). + Excellent armor class (−6). + Low base level (7) allows low level characters to stay polymorphed for the normal duration. + Fire and poison resistant, see invisible. +/− mediocre hit dice (7) − You will break your shirt, body armor, and cloak. − Cannot wear boots.
c cockatrice	+ Can lay eggs to produce good pets. + Can stone most other monsters. + Poison and stone resistant. − Poor hit dice (5) and poor armor class (6). − You will drop your weapon and all armor.
w purple worm	+ Can engulf and digest most other monsters. + Can lay eggs to produce good pets. + Excellent hit dice (15). − Poor armor class (6). − You will break your shirt, body armor, and cloak. − You will drop your weapon, gloves, shield, helmet, and boots. − You can be stoned by engulfing cockatrices or Medusa. − Not good for attacking groups of monsters.
b gelatinous cube	+ Can eat organic rings. + Can paralyze most other monsters. + Fire, cold, shock, sleep, poison, acid, and stone resistant. − Poor hit dice (6) and very poor armor class (8). − You will drop your weapon and all armor. − You will break your shirt, body armor, and cloak.
r rock mole	+ Can eat metallic rings and amulets. + Can dig through walls. − Very poor hit dice (3). − You will drop your weapon and all armor.
U umber hulk	+ Can dig through walls. + Can confuse most other monsters. − You will break your shirt, body armor, and cloak. − Can't safely attack cockatrices.
X xorn	+ Can eat metallic rings and amulets. + Can phase through most terrain. Obtain gems and gold entrapped in walls. Rob vaults. Reach Master Assassin at the Rogue quest. Find the vibrating square fast. + Good attacks (1d3+1d3+1d3+4d6). + Very good armor class (−2). + Strength 18/**. + Fire, cold, and stone resistant; doesn't breathe. − You will break your shirt, body armor, and cloak.

Messages

Become what type of monster? [type the name]

You polymorphed while you had polymorph control, and can select a monster to attempt to transform into.

Would you like to become a <wolf/jackal/rat>?

As above while you have lycanthropy and a random shapeshift or other form of polymorph would have triggered.

You feel like a new <man/woman>!

You polymorphed into your own race, either willingly with polymorph control or with a ¹⁄₅ chance while trying to turn into another monster; the latter can occur regardless of polymorph control.

Variants

Some variants implement major changes to polymorph mechanics that may affect polyself with polymorph control.

SLASH'EM

In SLASH'EM, doppelgangers gain intrinsic polymorph control at experience level 9, making them an excellent race choice for newer players, as controlled polyself makes them extremely powerful relatively early in the game. Without polymorph control, they can only reliably turn into monsters whose corpse or tin they have eaten, or whose monster level is equal to or lower than their current level.

Furthermore, the number of attractive polymorph targets in SLASH'EM is significantly higher. Some worthwhile forms (in addition to those listed above):

• Giant shoggoths are about the most powerful form, making short work of just about any monster, including One-eyed Sam. They are stoning resistant, can eat metal, are quite fast, and have teleport control. Unfortunately, they are also blind and have no hands. Thus, they make poor traveling forms, but are excellent for problem-solving.
• Crystal golems are too large to wear body armor, but intrinsically possess magic resistance, reflection, fire, cold, sleep and shock resistance. They will always have 300 HP as well. While their melee attack only does the damage of your wielded weapon/bare-handed combat abilities, they also possess a random breath weapon, possibly including disintegration.
• Master mind flayers are still a good choice, but in SLASH'EM they oddly have fewer brain-eating attacks than normal mind flayers.
• Fire vampires and star vampires are breathless, regeneration, flying, and make excellent fighting forms—they are also considered same-race (and thus unusable) for a vampire hero.
  • Fire vampires can wear all types of armor, give out radius 2 light, have 24 speed, a base level of 12 (same as a vampire lord), a base AC of 0, and additional attacks including a fire touch and level-draining bite.
  • Star vampires can wear all types of armor excluding body armor (shirt, suit/robe, cloak), have 18 speed, base AC of −5, a base level of 18, and can easily mow down enemies, doing up to 12d6 damage with six tentacle attacks per turn.
• Gugs can wear all regular things, and have a paralyzing attack and 18 speed.

Note that in SLASH'EM, forms that have a contact attack (bite, tentacle, claw, touch, etc.) will refrain from using that contact attack against a monster with a passive stoning attack (cockatrice, chickatrice, basilisk, or asphynx), but you still need to exercise caution. Contact attacks will be disabled only if: (1) you attack with a wielded weapon, and (2) the monster is in the same form for the first attack and subsequent attacks. Thus, clawing, biting, or butting a cockatrice without wielding a weapon will stone you, but hitting one with a sword as a master mind flayer or vampire will not; that is, unless the cockatrice was polymorphed into (for example) a troll, and an early attack caused the troll to drop below 1 hp and revert to cockatrice form, in which case the subsequent attacks will still hit the cockatrice and result in a stoning instadeath. This latter case may be a bug. Note further that this limits polyself options for doppleganger monks who are attempting the weaponless conduct; they will always attempt their contact attacks.

dNetHack

In dNetHack, notdNetHack and notnotdNetHack, both The Silver Key and The Hand-Mirror of Cthylla (an equivalent artifact to the Silver Key for Binders) grant polymorph control while carried.

The Alignment Thing is a spirit that confers polymorph control while bound.

SlashTHEM

In SlashTHEM, doppelgangers instead gain intrinsic polymorph control at experience level 25, making the ring of polymorph control much more valuable for controlled polymorphs in the interim.