The first thing to do is to dig a tunnel vertically upwards and fill it with ladders. The second one puts on an Elytra. Now you go all the way up into the tunnel and sneak. Then you stop sneaking and climb down, but you activate the elytra flight with double jump. The result is split into two options: First is that you fall down really fast and when you're in survival mode or adventure mode you die within seconds. (only 1.9-1.12)
Second is that the game kicks the player out of the game for: Invalid move player packet received. (only 1.13)