Green lights in spells

[zgirnius]

No: HPFGUIDX 147338

Carol:
> Carol, still certain that an AK is not the only spell that gives off a
> green light, but that's another topic so I won't go there

zgirnius:
Well, you are absolutely right. When Ron tries to jinx Draco in CoS, 
his (broken) wand backfires and causes a jet of green light to hit him. 
The result is that he starts to vomit up slugs. 

Also, in GoF after the Quidditch World Cup, when the Death Eaters show 
up at the campsite, there are flashes of green light. Since noone 
(including the newspapers) mention any use of the Unforgivables in that 
incident, I do not think this was a Killing Curse being cast. It was 
likely the levitation spell used by the Death Eaters to torment the 
unfortunate Muggle caretaker and his family.