Perhaps a sort of orbital cannon.
You place down a piece of gold ore, and a 3x3 stream of lava shoots from the sky, cutting through everything but bedrock. It then makes sort of an invisible field for the rest of the match that, if anyone enters is, dies, and the player laucnh the cannon gets points for it. Unless team kill, obviously. Then points should be removed. But it's highly expensive and can only be used once every 1000 rounds.
And some kind of AI has to post "Ion Cannon charging" in the chatbox, signifying it can be used, or it won't work anyway. Basically, it's first come, first NOT DEAD.
I'm certain this would never be made though.