The premise of the game is "Knock everyone else off the platform into the lava." Once four players step onto some pressure plates a countdown starts and everyone gets TP'd to a corner of a square platform above lava with a wall around it and a gap in between so that players can fall into the lava but not out of the game. Everyone receives a cactus with the stats "Sharpness -2, Knockback (insert number based on how big the platform is). KB 2 seems to work best. If you hit the lava you don't die, just teleport out of the game.
I built a prototype of it but it isn't great. Take from this post what you will.
