Inspired by this answer:

(Side note: "Reducto" would be a better counter to AK than Expelliarmus because it takes two less syllables to cast so you have a wider window, but you'd have to make sure to hit either their wand arm or their head to prevent them from finishing the curse, so...)

Many spells in the Harry Potter universe are specific in their target/range (Petrificus Totalus) or limited in scope (can't Alohomora a door that's already unlocked). Other spells, we see an effect on a whole body/object, or the immediate effect doesn't change the end result (the specific physiological mechanism of a killing curse usually isn't important).

Could I...

  • Reducto just one leg of someone's pants or a branch on a tree?
  • Crucio someone's toe without causing them pain over their whole body?
  • Imperio just someone's fist so they couldn't stop hitting themself?
  • Wingardium Leviosa just the end of the bed so I could slide a rug under it?
  • Accio page 5 without getting the rest of the book?

Those are just examples. We do see examples of incomplete spells when the students are in class (in Transfiguration, Ron turns Scabbers into a hairy goblet with a tail). Is it possible to intentionally use spells that seem to affect whole bodies or whole objects on just a part of them?

  • 3
    Are you planning to Engorgio something?
    – Valorum
    Commented Dec 2, 2018 at 9:46
  • 1
    Imperio is a bad example. Imperio is aimed on one's consciousness and awareness. You can't Imperio an inanimate object to do things because it doesn't have brain to control. Yes, you can use Imperio to control only one hand, but you still do it through affection one's brain and perception as whole. As for other things, I believe it's a matter of one's skill and concentration.
    – Shana Tar
    Commented Dec 2, 2018 at 9:49
  • Ton Tongue Toffees appear to only engorge the tongue and in Cursed Child we have the following ALBUS: "Cedric used a Bubble-Head Charm to swim through the lake. All we do is follow him in there and use Engorgement to turn him into something rather larger. We know the Time-Turner doesn’t give us long, so we’re going to be quick. Get to him and Engorgio his head and watch him float out of the lake — away from the task — away from the competition . . ."
    – Valorum
    Commented Dec 2, 2018 at 11:56
  • 1
    This was a topic in the fanfiction Harry Potter and Methods of Rationality where Harry transforms only a part of the object. Commented Dec 2, 2018 at 16:34

3 Answers 3


Of course it is. You've already answered your own question. In JK's world it is even explicitly given that the intent of a spell is significant. For another concrete example, in the very first film we see Hagrid intentionally transform Dudley to have a pig's tail. No other part of Dudley was modified. Likewise, we see Harry's broken nose fixed by Tonks (in the books) or Luna (in the film, IIRC).

  • Hagrid explicitly says he was trying to turn the whole of Dudley into a pig, but that the spell must have failed because he was so pig-like already (a poor cover up for the fact that he's just not a particularly competent wizard, having been expelled from Hogwarts), so that's a bad example. Commented Dec 2, 2018 at 14:10
  • Additionally, if only Harry's nose is broken, a repair spell will have no effect on the parts of his body which are not broken. Commented Dec 2, 2018 at 15:13
  • Okay, so focus on the word "intentionally" has confused some readers as to the point being made: as for the OP's question: yes a spell can be made to work inpart, whether intentionally or not. It follows that partial/focused spells can be performed intentionally. How easily this is done depends entirely on the character of the spell being cast.
    – Dúthomhas
    Commented Dec 3, 2018 at 3:29

Both can happen, depending on the type of spell you use. Take "Petrificus Totalus" for example. It can freeze a person entirely, but it's a longer chain of words. I assume the greater the power of the spell, the longer it takes to cast, with the exception of the curse spells. To limit the scope I would assume, based on the system being used, you could change different parts of this. There are such things as people who experiment with spells in the series, as that's how Luna's mom died. So as petrificus totalus means "Totally petrified", I would assume it would be certain latin phrases. The user is channeling this through the wand, which is why they need it. A second factor, unrelated, is that they must have wizard blood, which would delve much more deeply into the history. If you said a random latin word without a wand nothing would happen. It's also all in the word, as you can see throughout their teachings, especially within the notorious "Wingardium Leviosa" scene.


Lockhart successfully removes Harry's arm bones in the second book without removing all his bones. There are two cases possible here:

1) Either the spell works bone by bone and thus it does not partially affect , and Lockhart removes Harry's arm bones one by one. I find this unlikely, because he does it in an instant.

2) Lockhart wanted the spell to remove only the bones in Harry's arm, which then answers your question that "yes ,spells can have partial effects on the whole body".

  • Lockhart was trying to mend Harry's broken bone - not remove. Also, bones could be considered individual objects rather than just parts of a skeleton. This is another good example of a spell gone awry, but it doesn't answer my question.
    – miltonaut
    Commented Dec 3, 2018 at 21:57

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