Bunker Breach

Quickstart

1. Install the .mcaddon file and apply both the Behavior Pack and Resource Pack to your world.
2. Start a new or existing survival world and head underground — dig a cave, tunnel, or sealed base.
3. Once you're below ground with a ceiling over your head, the mod activates automatically. No crafting or commands needed.
4. Watch your action bar for warning messages. When a breach triggers you'll see either "Cave breach: zombies are flooding the dark stone." or "Bunker breach: light will not keep the dead out."
5. Hostile mobs will begin spawning around you. Prepare defenses before you go deep.

Overview

Bunker Breach transforms underground play into a persistent survival challenge. The mod continuously scans every player's position and environment. If you are in a low, covered area — a natural cave or a constructed underground base — the mod forces hostile mob spawns regardless of your light level. Torches and lanterns alone will not protect you. You must actively defend your space.

What It Adds

• Automatic breach detection — the mod silently monitors all players every few ticks and classifies their surroundings as either a natural cave or an enclosed underground base.
• Breach mobs — all hostiles spawned by this mod are tagged internally as bunker_breach_spawned, making them identifiable and useful for command-based filtering or scoreboards.
• Action bar alerts — context-sensitive warnings appear on screen whenever a wave spawns.

Abilities And Mechanics

Cave Zones

When the mod detects you are in a natural cave environment, it applies a heavily zombie-weighted spawn pool — zombies are 12× more likely to spawn than other hostile mobs. Expect relentless zombie floods rather than a varied assortment of enemies.

Underground Base Zones

When the mod identifies a player-constructed or enclosed underground base, the pressure increases:

• +15% extra hostile spawn pressure compared to a standard cave.
• 50% active breach chance per scan cycle while a player is inside — meaning roughly every other scan tick can trigger a new wave.
• Light level has no effect. A fully lit, walled-off bunker will still be breached.

Internal Caps

To prevent the world from being completely overrun, the mod enforces internal mob count caps. Waves will not stack infinitely, but the pressure remains constant as long as you stay underground.

Action Bar Feedback

Progression And Strategy

Because light management no longer guarantees safety underground, you'll need to rethink how you build and explore:

• Perimeter control — wall off all entry points and use doors, trapdoors, or iron bars to slow mob movement. Gaps in your perimeter are death sentences.
• Trap networks — pressure plates, tripwires, lava traps, and fall pits are far more effective than lighting alone. Layer multiple trap types to catch waves coming from different angles.
• Active defense — don't stay AFK underground. Breach mobs spawn continuously while you're present, so passive setups must be robust enough to handle ongoing waves without your attention.
• Escape routes — always have a way to retreat to the surface. If your defenses collapse, getting above ground stops the breach pressure immediately.
• Resource management — the constant mob pressure means armor durability, food, and weapons deplete faster than in a normal playthrough. Stockpile before going deep and set up renewable farms near or above the surface.
• Going deeper increases risk — the longer and deeper your underground footprint, the more exposure time you accumulate. Plan expeditions with a clear objective and exit strategy.