It just occurred to me while reading DH a while back. In HBP (maybe before) it's hinted rather strongly that spells are lifted once the caster dies. For example; Dumbledore's Body Bind Curse on Harry. When Dumbledore dies, that spell is automatically lifted. In my opinion, this suggests that spells in some way need to be "held in place" by a living thing, right?

That, though, raises another issue. How were Moody's "Anti-Snape" jinxes and curses at Grimmauld Place kept in place? After all, he died before Harry & Co. returned to GP in book 7.

Any ideas on this?

I think how it works is: permanent spells, ie. Permanent Sticking Charms, the Anti-Snape Jinxes or anything you can walk away from and leave it working will survive you, but temporary spells, ie. those you can't cast another spell while using them, will end when you die.

Yeah, well, I guess that makes sense.
But then, I think there'd be "categories" of permanent, temporary, "focus only" and "instant" spells, for want of better terms.
I totally forgot about the Permanent Sticking Charms, but they'd obviously go into the permanent category, where spells stick around even after their caster is gone.

Temporary would include Stupefy, Body/Leg binding curses and the like, I guess.

By "focus only", I mean spells that are only effective as long as you focus on keeping them active - Wingardium Leviosa, Cruciatus, and possibly Imperius, or is that more like the previous category.. hmm.. :P

The instant category pretty much speaks for itself - Expelliarmus, Avada Kedavra, spells that, in short, do one thing and leave it at that.

This would make sense for spells that change something, but not spells that require more "power" to work. And that's my problem with the Anti-Snape jinxes/curses - it wasn't like a creature, more like an active spell set off when the house was entered - and this still doesn't make all that much sense to me. Do they have spell batteries, or what!

Although, as I'm writing all of this, it occurs to me that the solution might be simpler: some spells are really more like enchantments. Whereas Stupefy actually changes its target, knocking it out and paralyzing it, other spells like Body Bind curses could just use a constant stream of "magical power" to keep its target immobile.

... That still doesn't explain the Anti-Snape Jinxes, but does a rather better job at the rest.

I agree with Silence is Golden. I say that there are different categories.

I'm also of the "different categories" camp. Some spells require concentration or they break, like Cruciatus. Others "take" and stay active until the countercurse is used, like Impirius (which may break when the caster dies, I'm not sure) or Permanent Sticking Charms.

However, the names give a vital clue: Charms, Enchantments, Spells, etc.

-Phil

"Quini, quidi, quici" - I came, I saw, I played a little quidditch.