Ice Spider Den

The Ice Spider Den is an underground structure added by Iron's Spells 'n Spellbooks. It generates in the Overworld, in snowy and icy biomes, and is one of the mod's horror structures. Its interior is a maze of frozen caverns and dungeon rooms, guarded by Strays and by the Ice Spider that the mod also uses for its rain-time patrols. Players seek it for the mod's jewelry, the Arcane Essence in its chests, and the Frozen Bone used in the furled map that locates it.

Generation

The structure is placed in the Overworld, in the 33 biomes of the has_structure/ice_spider_den biome tag. Most are snowy or icy biomes, such as Snowy Plains, Snowy Taiga, Ice Spikes, Frosted Caves and Snowy Beach. The tag also includes several non-snowy biomes that the pack keeps, such as Cold Desert, Gravel Desert and Spires. Mountain and ocean biomes are excluded.

The structure uses random-spread placement with a spacing of 60 chunks and a separation of 35 chunks. These are the in-game values after the pack's Sparse Structures scaling. The den is rare: about two appear per 26 km² in observed worlds. In frozen terrain its biome tags overlap those of the Impaled Icebreaker, so the two structures compete for space.

The den starts at the surface. Its start piece is a fort built on the ground, and the rest of the structure extends downward from it, so the visible part above ground is only the fort. The structure is generated in the underground decoration step with its start height projected to the world surface. Its typical footprint is about 144 by 124 blocks horizontally and 130 blocks tall. The start pieces use the "beard" terrain adaptation, which blends the fort into the ground around it.

Layout

The den has three connected branches, plus a single basement room.

• Fort. The surface start piece. Staircases and transition pieces lead from the fort into the cavern branch or directly into the dungeon branch.
• Cavern. Open frozen caves with upper and lower openings, a stairwell and extension pieces. Extensions include a circle henge, broken pillars, four ice spike variants, a frozen pig, an egg and a mithril vein. Mithril ore is part of this branch's extensions.
• Dungeon. Corridors of stone brick and cobbled deepslate, built from junction pieces (starting junction, T-junctions, cramped and snowfall junctions, and collapsed variants), straight and diagonal cave connectors, and dead ends with rubble. Rooms include a ballista room, a cell, a barrel-rack room, a book room, a snow-chest room, a 2×2 lounge, a pot room, a solid room, a storage room and a secret cave chest room.
• Room decorators. Dungeon rooms are finished with 5×5 decorator pieces: barrel piles, cobwebs, a fountain, pots, rubble piles, snow, a spawner, a statue, and tables with chairs.
• Basement. A single basement template with its own chest table. It holds the best loot in the den.

The structure processor makes the den look weathered. Some blue ice becomes packed ice, some mithril ore becomes blue ice, and some blue ice becomes stone. The stone brick and cobbled deepslate blocks partly rot, with an integrity of 0.95. The player statues in the den are randomized by a separate processor, so the statues differ between dens.

Inhabitants

The structure templates place Strays. The spawner decorator is one of the 5×5 room decorators in the dungeon branch.

The Ice Spider is the den's signature mob. It has 50 max health, 20 armor and 0.6 knockback resistance, and it uses pounce and grapple attacks. It is also the mob of the Ice Spider patrols, which are separate from the structure. During rain, the server rolls about a 50% chance to start a patrol near a random non-creative player who is in a snowy or icy biome. The interval between rolls depends on the number of grouped players, with a random extra delay of up to 3 minutes. The patrols can be turned off with the iceSpiderPatrols setting, which is on by default.

Loot

The basement is the most valuable room. Its Arcane Essence drop is guaranteed, and it has a 3% chance each for the Amulet of Concentration, the Conjurer's Talisman and the Silver Ring. The tower chests also have a guaranteed Arcane Essence, along with rarer rings and amulets: the Frostward Ring, the Ring of Recovery, the Amulet of Teleportation, the Ring of Invisibility and the Poisonward Ring. The pot rooms are the best source of Frozen Bone. The spawner reward chests give enchanted books and ink.

Biomes (33): Snowy Plains, Snowy Taiga, Snowy Badlands, Cold Desert, Muskeg, Tundra, Cold Shrubland, Cold Boreal Taiga, Tundra, Frozen Pine Taiga, Snowy Coniferous Forest, Auroral Garden, Wintry Forest, Snowy Fir Clearing, Ice Marsh, Gravel Desert, Snowy Beach, Glacial Chasm, Dead Forest, Siberian Taiga, Snowblossom Grove, Snowy Maple Woods, Wintry Lowlands, Ice Spikes, Spires, Snowy Cherry Grove, Hot Springs, Frosted Caves, Frozen Cliffs, Rocky Shrubland, Icy Heights, Cold Deciduous Forest (Removed), Frozen Tundra (Removed)

Mobs placed in the structure: Stray

Chest loot: irons_spellbooks:chests/filler_storage_loot

Item	Chance	Avg. stack
Cobweb	81.7%	1.6
Rotten Flesh	54.7%	1.3
Charcoal	36.0%	1.1
Arcane Essence	28.3%	2.5
Apple	27.3%	1.1
Book	25.3%	1.1
Common Ink	18.7%	1.0
Emerald	14.3%	1.1
Air	7.0%	0.0
Uncommon Ink	3.7%	1.0
Blank Runestone	0.7%	1.0
Rare Ink	0.7%	1.0
Scroll	0.7%	1.0

Chest loot: irons_spellbooks:chests/ice_spider_den/basement

Item	Chance	Avg. stack
Arcane Essence	100.0%	20.7
Frozen Bone	94.3%	2.5
Ice	94.0%	7.9
Snowball	91.7%	3.8
Cobweb	86.7%	7.1
Emerald	84.7%	4.5
Ice Venom Vial	69.0%	1.5
Blank Runestone	58.0%	1.0
Diamond	34.3%	1.2
Amulet of Concentration	3.3%	1.0
Conjurer's Talisman	3.3%	1.0
Silver Ring	2.7%	1.0
Emerald Stoneplate Ring	2.3%	1.0
Fireward Ring	2.0%	1.0
Poisonward Ring	1.7%	1.0
Air	1.7%	0.0
Ring of Expediency	1.3%	1.0
Heavy Chain	1.3%	1.0
Ring of Recovery	1.0%	1.0
Frostward Ring	1.0%	1.0
Ring of Invisibility	1.0%	1.0
Amulet of Teleportation	1.0%	1.0

Chest loot: irons_spellbooks:chests/ice_spider_den/pot

Item	Chance	Avg. stack
Frozen Bone	28.7%	1.0
Emerald	16.3%	3.2
Cobweb	16.0%	2.0
Arcane Essence	13.0%	4.4
Iron Ingot	3.3%	1.0

Chest loot: irons_spellbooks:chests/ice_spider_den/spawner_reward

Item	Chance	Avg. stack
Air	33.7%	0.0
Enchanted Book	33.0%	1.0
Uncommon Ink	20.7%	1.0
Common Ink	10.0%	1.0
Epic Ink	1.3%	1.0
Rare Ink	1.3%	1.0

Chest loot: irons_spellbooks:chests/ice_spider_den/tower

Item	Chance	Avg. stack
Arcane Essence	100.0%	12.7
Cobweb	98.3%	9.4
Ice	97.3%	9.1
Snowball	95.0%	4.4
Air	79.3%	0.0
Spyglass	25.7%	1.0
Frostward Ring	3.7%	1.0
Ring of Recovery	2.7%	1.0
Amulet of Teleportation	2.3%	1.0
Ring of Invisibility	2.0%	1.0
Poisonward Ring	2.0%	1.0
Amulet of Concentration	1.3%	1.0
Emerald Stoneplate Ring	1.3%	1.0
Silver Ring	1.3%	1.0
Ring of Expediency	1.0%	1.0
Conjurer's Talisman	1.0%	1.0
Fireward Ring	1.0%	1.0
Heavy Chain	0.7%	1.0

Furled map

The den can be found with a furled map, which is crafted from Frozen Bone, Cobweb and Magic Cloth. The recipe is shown in the item's own page. A server config, furledMapSkipsExistingChunks, controls how the map search treats chunks it has already checked, and the default is on.

Tips

Approach the den in clear weather. Ice Spider patrols only spawn during rain, so a dry trip avoids them on the surface. Go in with full health and with ways to escape, because the cavern branch is a long open space and the dungeon branch has narrow corridors.

Get the Frozen Bone from the pot rooms before you head to the basement, since it is also the main ingredient for the furled map. The Frostward Ring is tagged as a freeze-immune wearable in the pack, so it protects against freezing in the caverns. The basement is the safest place to collect the Arcane Essence and jewelry, but the three-percent rings there are rare, so plan several visits.