The Undergarden

Overview

The Undergarden is a complete dimension mod that adds a dark, alien world located below the Overworld's Bedrock layer. The dimension features seven distinct biomes, four custom ore tiers with unique tool and weapon properties, over a dozen new creatures including a full boss fight, and a trading system with the dimension's native Stoneborn inhabitants. The flora and fungi of The Undergarden have adapted to grow without sunlight, creating a bioluminescent landscape unlike anything in vanilla Minecraft.

The core gameplay loop revolves around mining the dimension's unique ores (Cloggrum, Froststeel, Utherium, and Regalium), fighting off the invasive Rotspawn mobs that plague the land, and progressing toward the Masticator boss encounter. You can browse all 146 items and blocks on the Items tab above, and check the Recipes tab for the full list of 124 crafting recipes.

Biomes of The Undergarden

The Undergarden contains seven biomes, each with distinct terrain, resources, and mob spawns. Most of the dimension is covered in Deepsoil and Deepturf, the equivalents of Dirt and Grass, while Depthrock serves as the primary stone layer.

Forgotten Field

The plains biome of The Undergarden. Open, relatively flat terrain with Deepturf ground cover and scattered Tall Deepturf grass. This is where you will most commonly spawn when first entering the dimension. Dwellers and Gloompers are common here, and the open space makes it a decent spot for building a base.

Smogstem Forest & Wigglewood Forest

The two primary forest biomes, each dominated by their respective tree type. Smogstem Forests feature tall Smogstem trees and are your go-to source for Smogstem Logs and Sticks. Wigglewood Forests contain Wigglewood trees, which provide an alternative wood type with its own set of building blocks. Both forests feature Shimmerweed, a glowing ground plant that provides natural light.

Dense Forest

A thicker, more dangerous version of the forest biomes with denser tree coverage and more mob spawns. Droopvines hang from the ceilings here, which can be collected and eaten for minimal hunger restoration. Be prepared for more Rotspawn encounters in these tight quarters.

Barren Abyss & Smog Spires

The dangerous biomes. The Barren Abyss is a desolate landscape classified as a dead biome with minimal vegetation and heavy Rotspawn presence. Smog Spires feature towering rock formations with Smog Vents that emit particles and provide light level 15. These biomes contain Tremblecrust, the hardest stone in the dimension (harvest level 3, blast resistance 24), and its Loose variant that breaks when you step on it if there is nothing or another Loose Tremblecrust block beneath it.

The Otherside

A mysterious void biome within The Undergarden. Entities that fall below Y=0 in The Otherside are teleported elsewhere, unless the disableOthersideTeleportation config option is set to true. This is the most dangerous area in the dimension and should only be explored with endgame gear.

Ores and Materials

The Undergarden features four unique ores alongside Overworld ore deposits (Coal, Iron, Gold, and Diamond all generate in the dimension). Each Undergarden ore produces materials for a complete tool and armor set, with progressively better stats and unique properties.

Cloggrum (Harvest Level 1)

The entry-level Undergarden ore. Cloggrum tools have 286 durability, 5.0 mining speed, and 4.0 base attack damage, making them roughly equivalent to Iron tools with slightly better damage. Cloggrum armor provides 18 total armor points (3+6+6+3) with 1.0 toughness. Cloggrum Ingots can be broken into 9 Cloggrum Nuggets and reassembled, and the ore smelts in both Furnaces and Blast Furnaces. The Cloggrum tier also includes a unique Shield and Bars (decorative fencing).

Froststeel (Harvest Level 2)

The mid-tier ore. Froststeel tools offer 575 durability and 6.0 mining speed with 3.0 base attack damage. While the raw damage is lower than Cloggrum, Froststeel Swords inflict Slowness V for 30 seconds on hit, making them extremely powerful crowd control weapons. Froststeel armor gives 15 total armor points (2+5+6+2) but with an impressive 4.0 toughness, the highest of any Undergarden armor set. This means Froststeel armor is better at absorbing heavy hits despite having fewer raw armor points.

Utherium (Harvest Level 3)

The top-tier craftable ore. Utherium Ore smelts into Utherium Chunks (not ingots directly). Four Utheric Shards craft into one Utherium Chunk, and nine Utherium Chunks combine into one Utherium Ingot. Utheric tools boast 1,279 durability, 8.0 mining speed, and 3.5 base attack damage with harvest level 4. The Utheric Sword deals 1.4x damage against Rotspawn enemies, making it the ideal weapon for clearing the dimension's most common threats. Utheric armor provides 20 total armor points (3+6+8+3) with 3.0 toughness. Shard Torches can be crafted from Utheric Shards and Smogstem Sticks, giving you 4 torches per craft.

Regalium (Harvest Level 4)

The rarest ore in The Undergarden. Unlike the other ores, Regalium does not have its own tool or armor set. Instead, Regalium Nuggets serve as the dimension's currency for trading with Stoneborn. Regalium Ingots can be broken into 9 Regalium Nuggets. This ore is uncommon-rarity (green text) and should be saved for trading rather than hoarded in storage blocks.

Armor Sets

Three full armor sets are available from the standard ores, plus one special chestplate dropped by the Masticator boss. Armor durability is calculated per slot using a base multiplier: Boots (13x), Leggings (15x), Chestplate (16x), Helmet (11x), multiplied by the material's durability factor.

Cloggrum armor (factor 10) gives you 130-160 durability per piece and 18 total defense, a solid starter set. Froststeel armor (factor 20) doubles the durability to 260-320 per piece with 15 defense but 4.0 toughness, making it better against powerful attacks. Utheric armor (factor 36) is the top tier with 396-576 durability per piece, 20 total defense, and 3.0 toughness.

The Masticated Chestplate is a special boss drop crafted from Masticator Scales. It provides 6 armor points for the chest slot (compared to Utheric's 8) but comes pre-enchanted with Thorns V, which cannot be removed. With a durability factor of 17 and 24 total armor points if you could wear a full set (though only the chestplate exists), it is best paired with Utheric pieces for the remaining slots.

Special Weapons and Items

Cloggrum Battleaxe

An Epic-rarity weapon that uses the Cloggrum tool tier with +5 attack damage and -3.5 attack speed. It comes pre-enchanted with Knockback IV that cannot be removed, and its durability is tripled compared to normal Cloggrum tools (858 total). This is a single-stack item designed for crowd control, sending enemies flying with every hit.

Slingshot

A ranged weapon crafted from Smogstem Sticks and Twistytwig. The Slingshot uses Depthrock Pebbles as ammunition, which can be obtained by crafting Depthrock into 9 pebbles each. It provides a reliable ranged option in a dimension where Bows and Arrows are not readily available.

Throwable Items

The Undergarden adds several throwable items. Blisterbombs are crafted from Rotten Blisterberries and Twistytwig, and function as explosive projectiles with a stack size of 8 and a 2.5-second cooldown between throws. Rotten Blisterberries (harvested from Blisterberry Bushes alongside regular Blisterberries) can be thrown directly with a 1.5-second cooldown. Goo Balls serve a dual purpose: they can be eaten (though they restore no hunger and apply the Gooey effect for 30 seconds) or thrown as projectiles with a 1-second cooldown.

Creatures of The Undergarden

Passive and Neutral Mobs

Dwellers are the dimension's primary livestock with 15 HP and a slow movement speed of 0.15. They drop Raw Dweller Meat when killed, which cooks into Dweller Steak (8 hunger, 0.8 saturation). Gwiblings are small fish found in underwater areas that can be caught with a Water Bucket to create a Gwibling Bucket. They cook into food worth 5 hunger. Gloompers are frog-like creatures with 20 HP that hop around the landscape peacefully. Scintlings are tiny ambient creatures with only 2 HP that glow faintly, immune to Goo slowdown and Blisterberry Bush thorns.

The Rotspawn

Rotspawn are the primary hostile mobs in The Undergarden, originating from a chaotic, mysterious realm. They come in four variants that form a clear threat hierarchy. Rotlings are the weakest at 10 HP and 3 attack damage, roughly Zombie-strength. Rot Dwellers are corrupted versions of the passive Dweller with 15 HP and 3 attack damage. Rotwalkers are significantly more dangerous at 40 HP, 5 attack damage, and 3 armor points. The Rotbeast is the largest standard Rotspawn at 80 HP with a devastating 10 attack damage and 3 armor, comparable to an Iron Golem in power.

All Rotspawn share a common creature attribute, which means the Utheric Sword's 1.4x damage bonus applies to every variant. Prioritize crafting Utheric weapons before venturing into heavily Rotspawn-infested areas like the Barren Abyss.

Other Hostile Mobs

Brutes are tusked creatures with 20 HP and 3 attack damage that drop Brute Tusks (4 Bone Meal each). They require non-peaceful difficulty to spawn. Blisterbombers are flying mobs with 25 HP and 128-block follow range that attack by throwing Rotten Blisterberries at players from above. They have 5 XP per kill and target players within 4 blocks of vertical distance. Stoneborn are unique because they are hostile but also function as merchants. With 50 HP, 10 attack damage, and 10 armor points, they are formidable fighters. They naturally attack Rotspawn and will chuckle after killing one.

Stoneborn Trading

Stoneborn are The Undergarden's equivalent of Villagers. Despite being classified as hostile mobs, they function as merchants when not angered. Right-click a peaceful Stoneborn to open their trading interface. They use Regalium Nuggets as currency, so keep any Regalium you find.

Stoneborn can be tempted with Regalium Ingots, Regalium Nuggets, or Regalium Blocks held in either hand, making them easier to lure into trading outposts. When in the Overworld, Stoneborn become confused and receive Nausea. If they stay in the Overworld for more than 15 seconds (300 ticks), they will explode with a power-3 explosion, so do not bring them through the portal.

Their trade offerings are randomized from a pool: they sell Blisterbombs (5 Regalium Nuggets), Underbeans (1 Nugget for 24), Diamonds (20 Nuggets), Emeralds (10 Nuggets), and Gold Ingots (5 Nuggets). They also buy Iron Ingots (4 Nuggets), Gold Ingots (5 Nuggets), Diamonds (10 Nuggets), Netherite Scraps (20 Nuggets), Lapis Lazuli (16 Nuggets), and Phantom Membranes (3 for 3 Nuggets). Each Stoneborn offers 5 random trades from this pool, plus one additional bonus trade. Stoneborn also naturally regenerate 1 HP every 2 seconds when not angry.

The Masticator Boss

The Masticator is The Undergarden's boss mob, a massive creature measuring 2.5 blocks wide and 4.0 blocks tall. It has 150 HP, 10 attack damage, 10 armor, 5.0 armor toughness, and 2.0 knockback resistance. A red boss health bar appears when you are nearby. The Masticator drops 25 XP on death and Masticator Scales, which are used to craft the Masticated Chestplate.

The fight has several mechanics to watch out for. The Masticator heals 25% of its current health every time it kills any living entity, so avoid bringing pets or allies that might die and feed it health. It launches targets into the air on contact, dealing knockback with a force multiplier of 4.0, so fighting near cliffs is extremely dangerous. It destroys leaf blocks when colliding with them and will jump to clear obstacles if it gets stuck. Its movement speed dynamically adjusts between 0.3 (idle) and 0.35 (chasing), and it follows enemies from up to 64 blocks away.

Flora, Farming, and Food

The Undergarden's plants grow independently of light level, so you can farm anywhere in the dimension. Deepsoil can be tilled with a Hoe to create Deepsoil Farmland, which functions identically to vanilla Farmland. It needs water within 4 blocks to stay hydrated and will revert to Deepsoil if trampled or left dry without crops.

Underbean Bushes grow on Deepturf and Deepsoil, producing Underbeans that restore 3 hunger. Blisterberry Bushes grow specifically on Ashen Deepturf and go through 4 growth stages. When harvested at stage 2 or above, they drop both Blisterberries (1 hunger, 3.0 saturation) and Rotten Blisterberries (used as throwable projectiles). Walking through Blisterberry Bushes at any growth stage deals 2 damage per contact (except for Scintlings, who are immune). Gloomgourds grow from Gloomgourd Seeds on stem plants similar to Pumpkins, and can be carved into Carved Gloomgourds or combined with a Smogstem Torch to make a Gloom-O-Lantern (light level 15).

Glowing Kelp grows underwater in The Undergarden, emitting light level 10. It can be smelted into Dried Kelp. Droopvines hang from ceilings and provide minimal food (1 hunger). Four types of mushrooms grow in the dimension: Indigo Mushroom (emits light level 2), Veil Mushroom, Ink Mushroom, and Blood Mushroom. Shimmerweed is a decorative glowing plant that emits light level 12, with Double Shimmerweed variants reaching light level 14.

Building Materials

The Undergarden provides a full suite of building blocks across its two wood types and three stone types. Both Smogstem and Wigglewood wood offer Planks, Stairs, Slabs, Fences, Fence Gates, Doors, Trapdoors, Buttons, and Pressure Plates. Smogstem Planks are used to craft Twistytwig (an alternative to Sticks used in Scaffolding and Slingshot recipes).

Depthrock (the dimension's basic stone) can be crafted into Depthrock Bricks, Cracked Depthrock Bricks, Stairs, Slabs, Walls, Buttons, and Pressure Plates. Depthrock requires harvest level 1 and has the same hardness as regular Stone. Shiverstone is a harder decorative stone (3.5 hardness, 12.0 blast resistance, harvest level 2) with its own Brick, Stair, Slab, Wall, Button, and Pressure Plate variants. Tremblecrust is the toughest building material (6.0 hardness, 24.0 blast resistance, harvest level 3) with Tremblecrust Bricks available. Cloggrum Bars serve as the dimension's Iron Bars equivalent.

Configuration

The Undergarden has a simple configuration file with one notable option. The disableOthersideTeleportation setting (default: false) controls whether entities are teleported when falling below Y=0 in The Otherside biome. Set this to true if you want to disable the void teleportation mechanic, which can be disorienting or dangerous on servers. The config file is located in the standard Forge config directory.