PETA takes over common sense
Disclaimer: This scene continues from where the fake Moody was showing the class the unforgivable curses. It picks off right where he explains the unblockable nature of the Avada Kedavra curse.
"And there's no counter curse…there's no blocking it." Finished Moody calmly.
Neville timidly raised his hand.
"Um…Longbottom?" asked The Scarred Professor, his magical eye twirling.
"Profesor, can't you just summon a cat or conjure some sort of living creature in the path of the spell?" asked Neville. "The curse can only take one life at a time right?"
The entire class sat momentarily stunned. Crouch Jr didn't know how Mad Eye Moody would handle this situation…but he did know how a ghetto rapper salesman with a daughter called "milkshake shanaynay" would handle this.
"A better question is…why do you hate cats so much?" asked Crouch Jr.
The class was metaphorically enervated and resumed ignoring everything Neville ever said, much to the advantage of the Death Eaters, who really didn't want to kill innocent cats.