Addon: Damage Deletes Chunk
Author: BebuPlayz
Damage Deletes Chunk changes survival into a challenge where health is not the only thing at risk. Whenever a player takes damage, the current chunk enters a visible countdown and is then removed, leaving a full-height void in the landscape.
A short fall, cactus, arrow or stray mob hit can erase resources, buildings and escape routes. Caves become especially dangerous, while boss arenas shrink after every mistake. The effect permanently changes the save, so careful movement and advance planning matter more than ordinary armor alone.

The system works in single-player and multiplayer. Groups can attempt a cooperative run, but damage taken by any participant continues to cut holes through the shared world.
Because deletion cannot be undone inside the add-on, use a separate challenge world or make a backup before starting. The objective may be defeating the Ender Dragon, surviving for a fixed time or simply seeing how long the terrain remains navigable.
How to install the add-on
Download the .mcaddon or .mcpack file, open it with Minecraft and wait for the import to finish. Then enable the resource and behavior packs in the world settings. If the add-on requires experiments, turn them on before launching the world.