all avatar mtg cards Ultra-Rare Card Is Already Selling For $13,000 Legendary Creature — Human Avatar Ally // Legendary Creature Rarity Airbender Ascension – Avatar MTG

At four mana its priced to fit into controlling and aggressive decks alike, and the fact that you can get it back off of either your opponents creatures dying or your own is huge for making it work in either strategy

Why its a contender: It is the benchmark for efficiency in damage spells

It only lasted a few months before being banned from both Modern and Commander

Maybe in a red/black deck you discard for the hit, and then recover the card you just discarded somehow

If any abilities controlled by that opponent trigger but losing 3 life causes them to lose the game, none of those abilities will be put on the stack