Minecraft wiki entry for Things_not_to_do, associated text: Assuming the player has found a way to get past the bottom bedrock layer of the Nether or Overworld or has an active portal to the End, they have access to the void. However, jumping into the void results in death. Once the player falls below Y=-64‌[Bedrock Edition only] or Y=-128‌[Java Edition only], they rapidly suffer from void damage, for which there is no immunity even in Peaceful difficulty or Creative mode‌[Java Edition only]. Each half-second below Y=-64‌[Bedrock Edition only] or Y=-128‌[Java Edition only] the player loses 4 health. To survive the void, the player would need Regeneration VIII or higher, which is inaccessible in survival. In addition, Totems of Undying cannot protect the player from death if they fall into the void. If the player dies in the void, they lose all of their items unless /gamerule keepInventory is set to true. Therefore, do not even think about jumping into the void under any circumstances. It’s one of the worst things you can do in the game.