The Great Convention

On any player's turn, if a player destroys
all creatures belonging to another player with an instant or sorcery, then the player who cast that instant or sorcery must lose 30 life.
On any player's turn, if a player destroys all
creatures on the battlefield with an instant or
sorcery, the player who cast that instant or
sorcery loses the game.
Use of atomics warrants retribution from all Houses.