Are there any instances in Harry Potter, where it is theoretically known that a spell with a particular effect exists, but nobody knows how to actually cast it?

An example could be that wizards know how to cast a 'heat ray' spell and can deduce by some in-universe rules that a 'cold ray' spell must exist, but nobody can work out how to do it.

  • 5
    So basically, do spells exist independently of the Wizards? Do the spells exist before the knowledge of them?
    – user160583
    Commented Feb 14, 2023 at 1:03
  • 3
    A constructivist might claim that you cannot prove that the spell exists unless you can write it down.
    – Adamant
    Commented Feb 14, 2023 at 3:19
  • I do not have the proper general knowledge, but this question basically begs for another one: what is the exact definition of a spell? Just the words themselves? The preparation of the wizard before casting? The "level" of the wizard? Etc... If it is just the words, it should be easy to infer. But there is some "proof" that even the quality of the wand is part of the spell (or, at least, influences the quality of the casting of the spell).
    – virolino
    Commented Feb 16, 2023 at 9:17
  • @Adamant Damn. Didn't know that's a thing even in maths, Thanks.
    – BCLC
    Commented Mar 21 at 15:44
  • @virolino does incantation + wand motion count? I said incantation in my original version, but it was removed in subsequent revisions.
    – BCLC
    Commented Mar 21 at 15:46

2 Answers 2



There do exist some spells in Harry Potter that only Voldemort could do such as -

Using the highly advanced art of spell creation, Voldemort was able to create four spells/magical items unique to him alone. These included being able to fly under his own power, creating the infamous drink of despair, the rudimentary body potion, and morsmordre. Theoretically, Voldemort could have done even more which just makes him scarier.

These four spell were known to Voldemort alone and now that he is dead nobody knows how to cast them.There was the spell of Unsupported Flight that Voldemort taught to Snape but he's dead too.

Then there is his rebirth -

Although many have tried, Tom Riddle is the only wizard to achieve complete rebirth. During his lifetime, Tom Riddle split his soul so many times that, when he was finally beaten, there was barely any humanity left. He was just a cursed soul trying to survive, which ultimately led to the scar on Harry's head.

Due to his obsessive fear of passing away, Voldemort was able to put into action a number of contingency plans should he be stripped of his physical self. After interacting with Peter Pettigrew though the ritual, Voldemort was reborn as his physical self, becoming the first and only to do so.

So another ability that is possible but since Voldemort is dead nobody knows how to do it.


  • 4
    "Only wizard to achieve immortality" - what about Flamel and the Philosopher's Stone?
    – fez
    Commented Feb 15, 2023 at 13:46
  • @fez I suspect the text means that he is the only one to die and come back to life preplanned.
    – TheAsh
    Commented Feb 15, 2023 at 14:54
  • 2
    "Only Voldemort knows how to actually cast it" is not an answer for "nobody knows how to actually cast it"
    – RalfFriedl
    Commented Feb 15, 2023 at 16:40
  • 1
    @RalfFriedl, i further clarified that since Voldemort is dead nobody actually knows how to cast those 4 spells
    – shanu
    Commented Feb 15, 2023 at 16:44
  • 3
    Barty, and probably the other Death Eaters, can cast morsmordre. Drink of despair and rebirth ritual are not even spells. And the question doesn't seem to be about spells that are lost because nobody remembers the details, but about spells that must exist but are not (yet) discovered.
    – RalfFriedl
    Commented Feb 16, 2023 at 6:38


Spells are invented by a wizward trying to achieve a specific effect. There are a lot of mentions throughout the books about wizards that are especially good in inventing new spells:

  • Voldemort inventing several spells
  • Snape inventing e.g. Sectumsempra and Levicorpus, just to mention two

Behind this link you can find a much longer list

And there are wizards who are not that good at all: look at Lunas mother who killed herself trying to invent a new spell

...she did like to experiment and one of her spells went rather badly wrong one day. I was nine." — Luna Lovegood, explaining her mother's death.

So if there was no wizard to invent a spell then there would be no spell.

If your question was: Are the EFFECTS of a spell that logically should exist but nobody came up with the correct spell yet: Probably... but we do not have enough information or any mention in the books for them.

But there are good examples for people looking for such spells. Take St.-Mungo hospital: They search for a cure for Nevilles' parents and to reverse the effect of the memory charm that fired back on Gilderoy Lockhart. Although I admit that this does not necessarily have to be a spell, it could also be a magic potion.

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