During the Main Phase, if exactly 1 monster with less ATK than your LP is Summoned and you have "Z-ONE" in your GY: Destroy that monster, and if you do, take 800 damage, then inflict 800 damage to your opponent
Modern There have certainly been attempts, but Modern is a fast, punishing format thats proven much too powerful for something like Gray Merchant of Asphodel
Duel 40: "A Piece of His Heart"
The ability for the Slaking ex card is Slacking Off, which ensures that this Pokmon only attacks Pokmon ex or V while in play, but the attack ability for this card makes that powerful punch worth it
SA Distribution: The Charizard Problem S9 has four SA cards: Charizard V (42,800), Arceus V (8,980), Lumineon V (1,380), and Honchkrow V (680)