Glass sword
Sword of instant death in the Ultima universe, a CRPG series. Sword breaks upon use killing the victim instantaneously, rendering it useless afterwards.
Dude: - "I'm gonna break this game by getting false coin and buying a bunch of glass swords."
Guy: - "That's cheating dude"
Dude: - "They're in the game, how is it cheating?"
Guy: - "..."
Guy: - "That's cheating dude"
Dude: - "They're in the game, how is it cheating?"
Guy: - "..."