so if i used this to turn someone into an egg and then crushed or eat it what would happen

WHY IS THERE NO OBJECT TO OBJECT???

Quote from ironpacifist >>

ok here's a question, troll gets turned into a elf permanently with this spell as a backstory

elf goes through life learns a class, let's say ranger

spell gets dispelled, do i retain ranger abilities as a troll with the condition that i use the troll stat block

 

 Considering that you have just become a troll, as the DM I would say no considering your new wisdom score.

i love getting to level 17 as a wizard and casting this on an abandoned cart or something of like and getting a young blue dragon companion or somethin like that it feels awesome

Question to clarify something here. Would a character or NPC capable of casting this spell be able to, in theory, transform their enemies into harmless and at least somewhat durable objects of no recognizable worth or significance and just place them in locations where they would become lost easily? For example, a gold coin given to a shopkeeper for some goods, a pebble placed among a mountain or gulch or a random wooden knick-knack to be sold to a curio owner. Could someone do this and just have that be how they get rid of rivals and people who would otherwise get in their way?

So question …

if I were a level 20 Crit chicken (oh wait wrong game ) I mean a Druid and I turned myself into a CR 20 elemental would I basically be immortal till it was dispelled or I was killed? 

plot of a campaign in which 4 arch druids TP themselves into immortal guardians of (insert artifact here) each of them taking the shape of a different high lvl elemental. 

thanks in advance for the input 

Always remember to check the bottom to see who can cast the spell. True Polymorph is only available to Bards, Warlocks, and Wizards.

Quote from mdrichey >>

Quote from Goddess_of_Chaos >>

...there’s nothing saying you don’t get the dragon’s legendary and lair actions with this spell...

 

Quote from Caladrel >>

You can have a lair and use legendary/lair actions in your new form...

 

Unfortunately, the MM intro states:

If a creature assumes the form of a legendary creature, such as through a spell, it doesn’t gain that form’s legendary actions, lair actions, or regional effects.

 While the MM does say this, I have to disagree with the conclusion you are coming to. I don't believe that this statement has any bearing on the polymorph line of spells. Allow me to explain my interpretation. If you look at the language used "assumes the form" both wild shape and shape change use this language. Both state you "assume the form" and both explicitly state you can not use legendary actions. The polymorph line uses a different language "you transform" and does not carry the statement about not being able to use legendary actions. With both wild shape and shape change you are not "becoming" said thing just using its form. This is why you do not take on the mental statistics. The polymorph line you "become" said thing and take on it's mental statistics. That is why I believe the polymorph line of spells are not affected by this statement. Unlike shape change you are not assuming the form but actually become the thing.

Turn the barbarian into an ancient white dragon, the cleric to a crystal dragon, the rogue into a deep dragon, and yourself into a brass dragon!

So turning someone or something into an object permanently until it's HP is 0 or whatever, is not possible with this 9th level spell?
Let's say I want to turn a person into a weapon? Or a decoration?

I can't do that for more then 1 hour?

can this turn someone into a pickle

Imagine if you used this spell to turn into a T Rex like with regular Polymorph.

Quote from bupdator >>

can this turn someone into a pickle

 Yes

I think this was confirmed in Sage Advice by Jeremy Crawford.  You do not get Legendary Actions, but you do get Legendary Resistances.

Can you please update this spell to include the Errata that you don't gain the legendary Actions+ Resistances of the creature you turn into. I've just spend 30 minutes planning an encounter with an Archmage, only to discover it does not work. This website should be the place where the most up to date vision of the spell should be included.

Say, if there was a character who could cast this on themselves, but they also happened to be a lycanthrope, would this stop them from using it on themselves?

Quick question, can you use this on yourself? Like, the range is sight but you can look at yourself in a mirror? And another thing, the 'Creature into creature' it says: or its level, if the targets doesn't have a challenge rating. So if you use this on yourself, and have multiclass fully into 2 class, 20-20, could you true polymorph into TIAMAT?

As others may have pointed out:

Polymorphing an already Polymorphed target (permanently or not) isn't technically viable according to DMG and PHB other than one spell overriding/replacing the other:

Combining Game Effects

Different game features can affect a target at the same time. But when two or more game features have the same name, only the effects of one of them—the most potent one—apply while the durations of the effects overlap. For example, if a target is ignited by a fire elemental’s Fire Form trait, the ongoing fire damage doesn’t increase if the burning target is subjected to that trait again. Game features include spells, class features, feats, racial traits, monster abilities, and magic items. See the related rule in the “Combining Magical Effects” section of chapter 10 in the Player’s Handbook.

Combining Magical Effects

The effects of different spells add together while the durations of those spells overlap. The effects of the same spell cast multiple times don’t combine, however. Instead, the most potent effect — such as the highest bonus — from those castings applies while their durations overlap, or the most recent effect applies if the castings are equally potent and their durations overlap.

For example, if two clerics cast bless on the same target, that character gains the spell’s benefit only once; he or she doesn’t get to roll two bonus dice.

[either you are stuck a dragon after the dragon-poly (since you can only have one Poly effect active) and deleted your previous Tier 4 True Poly caster or more reasonably, the DM blocks the dragon-poly since you end the True Poly: Dragon to Dragon Poly: Whatever, cancelling out the fact you're a Dragon who can polymorph into something else. Basically, DM should say, "you can't do that without reverting back to a Wizard/normal and casting True Poly again" or just let it fly I guess, lol (or delete your L20)]

As well as this important consideration in MM:

Legendary Creatures

A legendary creature can do things that ordinary creatures can’t. Legendary creatures can take special actions outside their turns, and a few can exert power over their environment, causing extraordinary magical effects to occur in their vicinity.

If a creature assumes the form of a legendary creature, such as through a spell, it doesn’t gain that form’s legendary actions, lair actions, or regional effects.

So, given:

Creature into Creature. If you turn a creature into another kind of creature, the new form can be any kind you choose whose challenge rating is equal to or less than the target’s (or its level, if the target doesn’t have a challenge rating). The target’s game statistics, including mental ability scores, are replaced by the statistics of the new form. It retains its alignment and personality.

The creature is limited in the actions it can perform by the nature of its new form, and it can’t speak, cast spells, or take any other action that requires hands or speech, unless its new form is capable of such actions.

The target’s gear melds into the new form. The creature can’t activate, use, wield, or otherwise benefit from any of its equipment.

Greatly limits some the more liberal/wider interpretations presented, even if the new form is permanent. A creature with a CR is worth experience and by default, an NPC which does not accrue levels. Unless under the effects of a spell like True Polymorph, PCs never have a CR, so leveling a character from 1 as any creature with a CR vs with a level is a reach.

Now, it does say:

If you turn a creature into another kind of creature, the new form can be any kind you choose whose challenge rating is equal to or less than the target’s (or its level, if the target doesn’t have a challenge rating). 

But that's because CRs are used to calculate the difficulty of a challenge given their level and therefore, can be used to translate your level, if the target, into a creature list by CR.

Therefore, this also limits what you can actually turn into, as far as creatures go, into generic creatures from the monster list, up to a CR equal to your level (which would be approaching 20) - RAW.

RAI? let it rip!

Challenge

A monster’s challenge rating tells you how great a threat the monster is, according to the encounter-building guidelines in chapter 3 of the Dungeon Master’s Guide. Those guidelines specify the numbers of adventurers of a certain level that should be able to defeat a monster of a particular challenge rating without suffering any deaths. An appropriately equipped and well-rested party of four adventurers should be able to defeat a monster that has a challenge rating equal to its level without suffering any deaths. For example, a party of four 3rd-level characters should find a monster with a challenge rating of 3 to be a worthy challenge, but not a deadly one.

Monsters that are significantly weaker than 1st-level characters have a challenge rating lower than 1. Monsters with a challenge rating of 0 are insignificant except in large numbers; those with no effective attacks are worth no experience points, while those that have attacks are worth 10 XP each.

Some monsters present a greater challenge than even a typical 20th-level party can handle. These monsters have a challenge rating of 21 or higher and are specifically designed to test player skill.

Quote from Destiny_Corrupt >>

Say a Bard uses True Polymorph on X to turn them into Y. One hour passes and X is Y. After a Long Rest, if the Bard uses True Polymorph on X(now Y) to turn them into Z, does it work? Does it Fail and do nothing? Or does it forcefully turn X back into X?

And if it works so that X can turn into Y and then into Z, how does dispelling work? X (as Z) turns back into Z? Turns into Y first, then back into X? Or turns into Y and is stuck as Y, Unable to become X again?

(I'm sorry, Super new and don't know a whole lot. Probably just overthinking the crap out of this...)

 If this process happened  X would now be Z and if dispelled would turn back into X.

This happens because you can only be effected by one instance of the same spell effect at a time, so when the second True Polymorph is cast it overrides the first.

Quote from GothGeekGaming >>

I think the  permanent part is only for Object into Creature. That said, a DM can call anything they want in their game.

 If that was the casr the part talking about the spell becoming permanent would only be under the Object to Creature part of the spell, but it is first mentioned in the main paragraph of the spell indicating it is an effect of the spell that takes place when used in ANY of the 3 possible ways.