What was the spell that hit Tonks? (Was: NVBL spell question)

[justcarol67]

No: HPFGUIDX 147892

bboyminn wrote:
><snip> 
> The AK Curse is somewhat unique in this sense. Any AK curse that
doesn't kill the person is a failed curse. Further the books seem to
imply that if the spell (the AK) is casted and it strikes then it is
fatal. <snip> From what we know, there are no powerful and weak AK's;
if it hits you, your dead. <snip>

Carol responds:
I'm not sure that I agree. Crouch!Moody told Harry's fourth-year DADA
class that if all of them together aimed their wands at him and yelled
"Avada Kedavra," he probably would not suffer so much as a nosebleed.
Of course, he could have been lying, but I think that both intent and
power count in an AK as they do in a Crucio (with the difference that
a Crucio has to be sustained and an AK doesn't). But *if* nonverbal
spells are generally weaker than verbal ones, as is implied by the
narrator's remark about Dolohov's curse, then perhaps a silent AK
could fail.

Certainly there was a lot of green light flashing around the MoM, yet
only Sirius Black died (from falling through the Veil, not an AK as
far as we know). So either the fresh-out-of-Azkaban DEs are a hopeless
bunch of rejects who can't hit the broad side of a barn (which doesn't
explain why Lucius Malfoy's AKs would miss their targets), or those
unnamed and apparently silent spells weren't AKs despite the jets of
green light, or the silent AKs failed. At least the one that hit Tonks
did. She fell down the stairs unconscious, but she didn't die.

So was the jet of green light that sent her to St. Mungo's a failed AK
(weak because it was silent) or was it something else? (Note that
there are no blinding flashes of light in the whole battle, so maybe
Harry misidentified the few that the narrator identifies as killing
curses--or being silent weakens them to mere "jets." Take your pick.)

Carol, thinking that an AK, like any other spell, would require
practice to master and wondering what the Durmstrang kids practiced on