Avenging Arrow doesn’t affect the damage the creature dealt. It isn’t retroactively prevented.
01-10-2012
wotc
It doesn’t matter what the creature dealt damage to. If the creature dealt damage to another creature or a planeswalker, it doesn’t matter whether that creature or planeswalker is still on the battlefield.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.