During the flight from Privet Drive, Snape sent a curse flying, attempting to hit Moody's pursuer, because Snape was helping Harry's cause. It accidentally hit Moody, which caused him to fall from his broom and die.
No, but seriously, I love it when it's sly. Haha, you had me in stitches at 'too much lettuce'.
also: R.I.P. to every character mentioned on this quiz. excluding the flobberworms.