It should be impossible to polymorph any unique monster; there are too many of them that can be trivially cheesed by turning them into something weaker.

Kandra race, based on the Mistborn books: a shapeless or shapeshifting invertebrate that can eat and imitate creatures with skeletons by “wearing” their bones. Would have the following properties:

• When you eat a bony corpse as a kandra, you are given the opportunity to turn into that monster.
• You might otherwise have the opportunity to digest the flesh but keep the skeleton (which would be a new item using corpsenm to track which monster species it’s a skeleton of) in order to wear it later. Skeletons would have to be heavy or bulky enough so that carrying lots of them around wouldn’t be feasible, and potentially corpses should rot into skeletons instead of completely vanishing.
• You can only achieve a perfect imitation of a monster by eating its fresh corpse. Wearing a skeleton at any other point results in a poorer imitation that would be penalized in some way: it could deal less damage, have terrible Charisma, and so on.
• When perfectly imitating a monster, other monsters might not attack you.
• Eating and replicating a corpse also takes time, which would be implemented as an occupation. If interrupted, your new form is imperfect. Possibly, the time needed to assume a shape from a skeleton decreases as you get more experienced and gain more levels.
• You can exist without any bones, but this means you are a weak, slow ooze monster (perhaps kandra should be in the “b” class).
• Hunger might not work the same way. Kandra in Mistborn do not need to eat, but for gameplay balance there should probably still be some need to keep seeking out food.
• Might be able to store some smaller items inside your body, protecting them from theft, damage, and destruction.
• Can pick locks with your “hands” by selecting “-“ as a lockpicking implement.
• Sources of acid would be especially damaging.
• These are a lot of advantages with few disadvantages; some special disadvantages might need to be created, such as certain types of elemental damage disrupting your body and forcing you to drop your skeleton.
• The system of Blessings in Mistborn (two magical spikes which all kandra must keep within their body at all times) could be used. Somehow losing the Blessings would be an instadeath.

New role based on a “loup du noir” archetype, possibly called the Lycanthrope - you start with a pelt, a new sort of cloak-slot armor that polymorphs you into a specific type of monster when you wear it. You also are inflicted with some sort of delayed lycanthropy - you won’t randomly polymorph into a monster like with standard lycanthropy, but after not using a pelt for a while, you do start feeling the urge to put one on, and if you still refuse, you are eventually compelled to put one on. (It isn’t specified what happens if you get rid of your pelt(s) by the time you would be compelled to wear one; possibly you just die from insanity, or else the addiction is implemented in some other way like continuous worsening HP damage.)

The form you get from wearing a pelt has some boosted stats from the base form - in particular, your carrying capacity and damage would be better than the stat blocks for the monsters suggest.

You could start with either a “default” pelt which is not very good, but can be turned into an ideal one later, or start with a specific animal’s pelt, which you can control with the pettype option. This role never starts with a pet.

Pelts might also work as a standalone concept or one that works with a druid, ranger, or caveman role:

• You can obtain a pelt by using a knife to skin the corpse of some monster that would reasonably have a pelt. This will probably be an occupation, and either its time or success rate will vary based on your knife skill and if you have a role-specific bonus.
• By using some sort of magic (instead of it being inherent to a role), you can transform into the animal whose pelt you are wearing.
• Pelts confer some benefit when worn as a cloak besides the ability to polymorph, which varies depending on the monster species, such as a boost to damage.

When you unpolymorph, you temporarily keep any intrinsics you had from that form and which you no longer have. How long it is before these intrinsics time out isn’t specified, but probably contains some random component so you can’t plan around when the intrinsic will lapse.

This was suggested for a hypothetical druid role, but noted that it doesn’t have to be a role-specific mechanic and could apply to other roles as well.

When you perform a controlled polymorph, you are only able to turn into monsters which have HD equal to or lower than your level. If you are using a mask, or if you are polymorphing randomly, it treats you as being 10 levels higher than your actual one.

Lycanthropic and vampire shapeshifting polymorphs are exempt from this restriction.

Dipping a corpse into a potion of polymorph “keys” the potion to that specific monster type: if it is used to polymorph the player or a monster, they will be turned into the same monster type as the corpse used. The corpse and potion are not consumed by being dipped.

If the monster is no-polymorph, nothing happens.

If the potion is used to polymorph an object, it does not do anything unusual, unless the object is a type for which species matters, in which case the potion changes its species to the keyed type, which can be useful for changing a figurine to something specific.

If in a variant that has potions of specific monsters’ blood, this can also be created by dipping polymorph into monster blood or vice versa.

Telepathy currently sees things with minds. Change it (or perhaps change only the amulet of ESP, leaving other telepathy the same) so that it sees things with souls instead of minds. Mostly this corresponds with the same monsters (with a few exceptions such as mummies which are animated by the soul of the dead person), but if a monster with a soul is polymorphed into a form that normally doesn’t, it retains its original soul, and shows up as its original form to ESP.

Additionally, ESP shows the spirit of a humanoid with a soul just after you kill it if you’re blind, making some angry or resigned gestures before fading away.

Polymorphed monsters appear as “hazy [monster]” in messages, to indicate to the player they will time out and go back to their normal form eventually.

Controlled polymorph does not ask you what you want to turn into. Instead, it picks a random monster and asks you whether you want to turn into that, and you can only say yes or no.

Chaos dragon: a dragon with polymorphing breath, and whose scales grant unchanging. The dragon also has unchanging naturally (which raises the question of what happens if you polymorph into it, then die).

Add a system for casting ritual spells: more powerful and more expensive spells which have some esoteric effects you can’t get otherwise. The main differences between ritual and normal spellcasting are that they consume valuable, hopefully non-renewable components, take a number of turns to cast instead of taking effect instantly, and may require you to be in or set up certain circumstances.

Various ritual spells that have been proposed:

• Ball spells which consume a gem as focus and create a ball of elemental power that hits surrounding squares but not you. (Long casting times would probably make rituals infeasible for combat though.)
• Temporarily increase your carry cap by a great amount. (Other new intrinsics as required.)
• Resurrect a corpse as a tame monster (necromancy).
• Grant temporary intrinsic life saving.
• Single controlled polymorph with a greatly increased duration.
• Summon a demon, demon lord, or demon prince. Requires 5 cursed candles and a marker (to draw the classic pentagram). If summoning a named demon lord, it’s either random or there’s some expensive way to control who shows up. The demon lord could be peaceful, but with current behavior this is useless. Possibly summoning them allows you to make a pact with them.
• Remove the graveyard status from a level (would need to be expensive, and perhaps involve the Book of the Dead, and multiple different headstones).
• Grow a tree. This consumes at least a piece of fruit. For anti-farming the tree should probably not produce fruit or bees when kicked.
• Create a portal between two levels of your choice (doesn’t work with the Amulet obviously, but otherwise works)
• Create an artifact (that is, you somehow imbue an item with properties it can’t normally get).
• Bless items. Consumes a blessed scroll of remove curse.
• Genocide a genocidable monster. Consumes a figurine of that monster plus other costly things.
• Reverse genocide a monster. The monster may or may not have to be normally reverse-genocidable. Consumes a figurine of that monster plus other moderately expensive things.
• Charge something. Requires a rare ingredient - perhaps a dilithium crystal.
• Summon tame elemental(s). Among other things, ingredients include: a potion of water, any beatitude (water); a rock (earth); lit candles, a lit oil lamp, or a lit potion of oil (fire); an amulet of magical breathing (air).
• Create a magic lamp. Needs an oil lamp (of course) and a figurine or mask of a djinni (or possibly a nearby live djinni).
• Make the current level non-teleport. Requires a scroll of teleportation and that the caster be standing on an anti-magic field at (?) either the start or the end of the ritual.
• Create a fountain. Requires a statue of a medium-sized or larger monster, which gets destroyed (by turning it into the centerpiece of the fountain). There may be potential for wishing abuse; perhaps the fountain should be flagged so that it can’t produce a wish-granting water demon.
• Turn a regular knife into an athame. Components include other bladed weapons with positive enchantments adding up to 20 or something; all of these charges will be drained to +0 in the creation of the athame. The resulting athame is +0, regardless of the charges on the component weapons or original knife.
• Create a tame golem or golems. Requires a large amount of total weight of objects made out of the golem’s material.
• Summon a coaligned angel or other minion of your deity as a pet.
• Create a tame wood nymph from a tree (only once per tree).

Ritual spells come in spellbooks like usual, but aren’t stored in your spell list. Instead, reading the spellbook prompts you if you want to begin its ritual and tells you the necessary ingredients and circumstances you need to satisfy as preconditions. If you meet all the conditions and answer yes, you initiate the ritual. (For simplicity, this should probably burn up / expend all the components instantly.) You cannot begin a ritual while in the process of casting another ritual; this should probably be implemented as a precondition.

Apart from the component cost, rituals act as a constant drain on your Pw until the ritual is complete. If something distracts you in the middle of the ritual, you can go take care of it and then resume the ritual as long as you have the Pw left to finish it. (You could also drink gain energy during the ritual.) The only way for a ritual to fail, possibly backfiring with bad effects, is for you to run out of Pw while it is incomplete.

In addition to its preconditions, each ritual also has some postconditions: common to all rituals is that you have been casting the ritual for at least some length of time, but there may be others, such as standing on the square where you began the ritual, or have another item, or kill a monster, or something. There may also be other conditions such as “moving off the space where the ritual started breaks and halts the ritual”.

Every time you stop casting a ritual (whether it succeeded or failed), it increments the spellbook’s spestudied field; the book will eventually disintegrate after casting it a certain number of times.

Add a Druid role: intended to be a more balanced form of SLASH’EM’s doppelganger race, druids are highly attuned to nature and possess innate shapeshifting abilities.

• You begin the game with polymorph control and get polymorphitis at XL 5 or so.
• Possibly you start with a wand of polymorph, or potions of it.
• Inventory could be severely restricted, so you have to figure out how to do most things through polymorph.
• You have the power to change into a tree, which will make most monsters ignore you. While in tree form, you are immobile but regenerate HP and Pw faster. Orcs might attack you with axes, a la Tolkien.
• Without extrinsic polymorph control, your polymorph control limits you to changing into forms with the M1_ANIMAL flag.
• Possibly have limited access to #polyself outside of wizard mode, so they can change intentionally and not randomly. Would work best as an ability with a timeout, or cost Pw outside of wizard mode.
• Possibly, the monsters you can polymorph into must have a certain base level or difficulty that’s tied to your XL somehow (maybe XL/2). If their base level is too high, you can’t polymorph into them.
• Your controlled polymorphs always succeed - you will never accidentally fail and “feel like a new woman” with the 20% chance that all other roles have.
• You are seriously bad at combat in your regular form, having very little weapon skill (nothing can be advanced to Expert, possibly not even to Skilled), and physically weak in your normal form. Combat in a polyform should be incentivized enough so that it isn’t really worth it to wear any armor. Maybe you should get to-hit and damage bonuses while in a wild form?
• Diminishing returns on polymorph time limit that prevent you from reusing the same form(s) over and over and over again. (This may actually be applicable as a general YANI for polymorph control).
• The critical balance needed is to make polyselfing powerful and awesome to play with and use for typical combat, but simultaneously polyselfing needs enough restrictions that it doesn’t just turn into Master Mind Flayer: The Game.
  • One proposed restriction: you can only turn into monsters you have already encountered, or if that is too lax, into peaceful or tame monsters adjacent to you at the time. The druid should be able to pacify most animalistic monsters to take advantage of this (temporarily?)
• The starting pet is a woodchuck (or wolf). Pantheon is probably drawn from Celtic mythology, though hopefully not overlapping with Knights.
• Some heavy polymorph / monster / player as monster tweaking is probably required, in the sense that there should, ideally, be valid reasons to exist in any given polymorphable form.
• You should keep the intrinsics from a polyform after you no longer have that form, but only temporarily, so they time out eventually.

Make #polyself a non-wizard-mode-exclusive command. When used in regular play, it will:

1. Cast the polymorph spell at yourself, if you know it.
2. Otherwise, attempt to activate a polymorph trap you are standing on.
3. Otherwise, fail like the #teleport command would when you are unable to teleport at will.

When you attempt to polymorph an item that has polymorph magic (wand/spell/potion of polymorph, tin of meat that may cause a polymorph when eaten, etc) it explodes and creates one or more monsters affiliated with polymorph magic, such as polymorph vortices (see YANI #3669), genetic engineers, or similar.

Polymorph vortices, a monster which has a passive polymorph attack (i.e. hitting it in melee polymorphs the attacker; hitting it with missiles polymorphs the missiles) and once per turn polymorphs either one random item from its inventory, a monster it has engulfed, or a random item from that monster’s inventory. Player-style magic resistance prevents the effects to a creature or its possessions that would otherwise be affected.

Uranium wands have a small but persistent chance of causing radiation-based effects: “[The wand] momentarily glows with a sinister green light!” or “The wand momentarily feels very warm!” When this happens, one of two effects happens, each with a 50% chance: the victim takes 2d6 points of damage unless poison resistant, or the victim polymorphs.

The chances are as follows:

• 1/100,000 per turn while carried in the hero’s or a monster’s main inventory (carrying it in a container makes it safe)
• 1/500 chance if zapped at yourself, up, or down, or if the wand is non-directional
• 1/2,000 chance if engraved with or zapped in a direction
• Stacking 12.5% chance per charge in the wand, up to a maximum of 75%, if it is broken or explodes, to any monsters in the 9 squares affected by the explosion

Eating a uranium wand as a metallivore should cause you to mutate (polymorph), either once immediately or by giving you some duration of polymorphitis.

If you polymorph uncontrolled while wielding a unicorn horn, you may become a unicorn corresponding to your alignment.

NetHack should contain something that turns you specifically into a newt.

Displacer beasts may drop a hide, which can be enchanted or otherwise crafted into a cloak of displacement. (Or else this could just work with a displacer beast corpse which could be enchanted/polymorphed/crafted, without requiring a new object for the hide).

Controlled polymorph does not allow you to become whichever polyable monster in the game you want. Instead, you are presented with a menu of several different random polyable monsters to choose one of.

Eating a wand of wishing polymorphs you into a djinni.

Hitting a shambling horror with polymorph should not polymorph it into something else; instead it should rerandomize its stats and attacks.

This would be better if shambling horrors were randomized per monster rather than per species; it doesn’t make much sense to polymorph a horror on dungeon level 20 and a preexisting horror on dungeon level 17, or new horrors that haven’t even generated yet, get rerandomized.

Artifact tinning kit that makes special tins out of corpses; the tins when eaten polymorph you into that monster.

Polymorphing while wearing crystal plate mail, leather armor, or iron mail can cause you to merge with the armor and turn into that respective material of golem (glass, leather, or iron), with the armor returning unbroken when you revert back to your normal form.

With polymorph control, you can only polymorph into creatures that you have seen before in the game. You can still opt to not choose something to turn into, which could still give you a random form.

In wizard mode, the #polyself command (and only that) enables you to polymorph into a non-allowed form, with a confirmation prompt and/or warning message.

A polymorphed monster will turn into a monster of similar difficulty to its current form, rather than a monster of difficulty appropriate to the current dungeon level.

When a container is polymorphed, its contents spill out onto its square rather than vanishing. The contents do not get polymorphed from the same source.

Polymorphing into any Tiny monster, or a Small non-humanoid monster, allows you to get free of any iron chain around your ankle even if your new form still has legs.

Make it so that dying in a polyform carries a severe, possibly permanent penalty, such as losing some Constitution, maximum HP, or forcing you to a low percentage of current HP regardless of what you had when you first polymorphed.

Eating too much royal jelly polymorphs you into a killer bee.

When you polymorph into a monster which reduces your carry cap so that you’re burdened or worse, you automatically unequip and drop your worn items until you are unencumbered.

New Biologist role, which revolves around polymorphing monsters, brewing potions (probably non-alchemically), and possibly collecting samples from monsters.

Possibly, they start with a number of potions of booze, but are penalized for drinking booze; it’s intended to use for brewing with samples. They also possibly have a guidebook describing recipes (other roles can do this too, but lacking a guidebook they won’t be able to do it very well).

Starting equipment may contain:

• Alchemy smock
• Gloves, probably leather but maybe padded
• Goggles, a new eye-slot tool made of plastic that protects your eyes from splashes and spits just like the visored helmet
• Knife
• Walking shoes
• Wand of polymorph (questionable)
• Tripe and vegetables to tame monsters

One take on the quest: it sees you fighting the Black Mold (a mold that constantly multiplies itself and attacks with random elemental damage, including possibly disintegration, when touched). The quest artifact is the Elixir of Immortality, but this is not possessed by the nemesis; instead you have to brew it yourself using an ingredient found on the goal level and which will be destroyed by the Black Mold if you don’t get there first. The Elixir isn’t needed; the quest is counted complete if you destroy all the Black Mold.

They can get Expert in only a few skills, including knife.

They are penalized for “animal testing”, which is polymorphing or otherwise abusing living peaceful or tame monsters. Or possibly it’s okay as long as the subject isn’t killed. However, they are rewarded for other forms of experimentation.

Add a random throne effect that polymorphs you into a level-appropriate royal monster.

Replace the existing polyself nerf that 20% of polymorphs turn you into your own race. Instead, have it so that the longer you stay polymorphed, each successive polymorph has a shorter duration. If you stay in your normal form for a while, polymorphs will return to their original duration.

Stat shuffling through self-polymorph should be slightly biased towards reducing stats.

When you fail to polymorph and get the “new man/woman” message, prior to this print a message that makes it clear that the polymorph fails. You don’t get this message when you deliberately try to polymorph into your own race.

Polymonsterless conduct: you never intentionally polymorph a monster. (Though defining “intentionally” is probably quite tricky.)

You can wish for “polymorph”, which makes you polymorph. Possibly you get control over the polymorph.

Spell of baleful polymorph: a beefed-up version of polymorph (or an advanced form) that, when it polymorphs a monster, allows you to determine what to change it into. Perhaps this does not work on pets, so you can’t give yourself a army of titans.

Polymorphing a corpse does not turn it into random food, but instead turns it into the corpse of a random level-appropriate monster. Discards any oextra information about the previously existing monster.

An artifact that occasionally polymorphs the monsters it hits.

Polymorphing into a big scary monster like a dragon or minotaur causes some monsters (failing a resistance roll?) to flee.

Polymorph beams stop at the first square on which there’s an object or a monster they affect. In addition, golem formation is made much more aggressive and item-destructive to discourage one-large-stack polypiling.

A race where you start polymorphed into a low level monster and with every level you gain, you can polymorph into a stronger monster.

If you polymorph, and are not helpless, all of your torso armor that has a delay of 1 or less and isn’t stuck under slower armor is automatically removed. This includes all cloaks and shirts.

The chance of failing to polymorph into a target monster (whether chosen randomly or intentionally) depends on the base level of that polyform relative to your own level.

Polymorph traps do not instantaneously polymorph you; instead they start a short timer during which the player has time to either stop the polymorph from occurring (through healing potions, or prayer, or some other decently common consumable) or put on a ring of polymorph control or amulet of unchanging. However, magic resistance no longer protects against this effect.

Polymorphing a highly enchanted object will vaporize it if it turns into something that normally can’t be enchanted that high.

Players can polymorph dungeon features by zapping a polymorph beam down at it, with some special cases:

• Gravestones can be created by polymorph and are more likely than other outcomes, but cannot be polymorphed into anything else. Trying to do so only polymorphs its epitaph.
• Polymorphing an altar angers that altar’s god and any attendant priest since you effectively destroyed their altar
• Fountains either cannot polymorph into anything besides headstones or have a very limited chance of becoming something else; this is to prevent the player from being able to generate a bunch of thrones from fountains.