October 31st 1981
Voldermort was so annoyed, but this was his opportunity. Both Neville and Harry were candidates to be part of the prophecy and they were both in the same place.
But, of course their parents had to be here too. So now he has more work cut out for him.
He never expected Lilly to refuse to move aside while he was trying to kill those brats. He finally relented and killed the ungrateful lady. And casted his killing curse, carefully aiming it at both boys who were side by side, but it backfired and he was now in an unimaginable state.