Though often seen as little more than vermin by unsuspecting city folk, cranium rats represent a terrible menace when gathered in sufficient numbers. On its own, a single cranium rat is a negligible threat, barely more dangerous than a common rodent; but when they come together, cranium rats form a telepathic hive mind, and the more rats that gather, the stronger the hive mind becomes, eventually granting them superhuman intelligence and great mental powers.
Cranium rats serve an unknown purpose, gathering knowledge and ferreting out secrets for reasons known only to them. Some sages believe they are the eyes and ears of some dark deity of knowledge, such as Norgorber; others posit some connection with the illithid god-mind, Ilsensine. Those who pry too deeply tend to be found gnawed to death by thousands of tiny fangs. Despite this, cranium rat packs can be invaluable sources of knowledge for those who seek them out, for they know the darkest secrets of the cities they call home.
Cranium rats are creatures of the Great Beyond, found in vast quantities in the cities of the Outer Sphere - Dis, Yanaron, Pharasma's Court, and of course, the Eternal City of Axis, where they congregate in vast swarms in the tunnels of Norgorber's realm. They are less commonly encountered on Golarion, save in great cities with high concentrations of spellcasters, such as Egorian, Quantium, or the great cities of Absalom and Goka.
A lesser cranium rat pack is made up of about 75 rats, an average pack about 150, and a greater pack about 300.
CRANIUM RAT
CR: 1/4
XP: 100
NE Tiny magical beast (extraplanar)
Init: +2; Senses: Darkvision 60 ft., low-light vision, scent; Perception +1
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AC: 14, touch 14, flat-footed 12 (+2 Dex, +2 size)
hp: 6 (1 HD)
Fort +2, Ref +4, Will +1
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Speed: 15 ft., climb 15 ft., swim 15 ft.
Melee: Bite +5 (1d3-4)
Space: 2-1/2 ft.; Reach: 0 ft.
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Str 2, Dex 15, Con 13, Int 3, Wis 13, Cha 3
Base Atk: +1; CMB: +1; CMD: 9 (13 vs. trip)
Feats: Weapon Finesse
Skills: Climb +10, Stealth +18, Swim +10; Racial Modifiers: +4 Stealth, uses Dex to modify Climb and Swim
Languages: Undercommon (can't speak)
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Environment: Any land or underground
Organization: Solitary, pair, nest (3-12), or minor pack (13-74)
Treasure: None
LESSER CRANIUM RAT PACK
CR: 2
XP: 600
NE Tiny magical beast (extraplanar, swarm)
Init: +2; Senses: Darkvision 60 ft., low-light vision, scent; Perception +8
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AC: 14, touch 14, flat-footed 12 (+2 Dex, +2 size)
hp: 19 (3 HD)
Fort +4, Ref +5, Will +4
Defensive Abilities: Swarm traits; Immune: Weapon damage
Weakness: Hive mind
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Speed: 15 ft., climb 15 ft., swim 15 ft.
Melee: Swarm (1d6)
Space: 10 ft.; Reach: 0 ft.
Special Attacks: Distraction (DC 12)
Spell-Like Abilities (CL 1st, concentration +0):
Once every 1d4 rounds - Mind blast (60 ft. cone, Will DC 14 negates, stunned for 1d4 rounds, level 4)
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Str 2, Dex 15, Con 13, Int 8, Wis 13, Cha 8
Base Atk: +3; CMB: --; CMD: --
Feats: Iron Will, Skill Focus (Perception)
Skills: Acrobatics +6, Climb +10, Perception +8, Stealth +14; Racial Modifiers: Uses Dex to modify Climb and Swim
Languages: Undercommon (can't speak)
SQ: Merge swarms
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Environment: Any land or underground
Organization: Solitary (see below)
Treasure: None
AVERAGE CRANIUM RAT PACK
CR: 5
XP: 1,600
NE Tiny magical beast (extraplanar, swarm)
Init: +6; Senses: Darkvision 60 ft., low-light vision, scent; Perception +15
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AC: 20, touch 20, flat-footed 12 (+2 Dex, +6 dodge, +2 size)
hp: 52 (8 HD)
Fort +7, Ref +8, Will +3
Defensive Abilities: Reflexive dodge, swarm regeneration, swarm traits; Immune: Weapon damage; Resist: Cold 10
Weakness: Hive mind
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Speed: 15 ft., climb 15 ft., swim 15 ft.
Melee: Swarm (3d6)
Space: 10 ft.; Reach: 0 ft.
Special Attacks: Distraction (DC 15)
Spell-Like Abilities (CL 4th, concentration +6):
Once every 1d4 rounds - Mind blast (60 ft. cone, Will DC 16 negates, stunned for 2d4 rounds, level 4)
Spells Known (CL 4th, concentration +6):
2nd (4/day) - Mirror image
1st (7/day) - Charm person (DC 13), expeditious retreat, magic missile
0 (at will) - Daze (DC 12), detect magic, flare (DC 12), mage hand, open/close, prestidigitation
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Str 2, Dex 15, Con 13, Int 14, Wis 13, Cha 14
Base Atk: +8; CMB: --; CMD: --
Feats: Combat Casting, Improved Initiative, Iron Will, Skill Focus (Perception)
Skills: Acrobatics +13, Climb +10, Perception +15, Spellcraft +10, Stealth +21, Swim +10; Racial Modifiers: Uses Dex to modify Climb and Swim
Languages: Undercommon (can't speak); telepathy 100 ft.
SQ: Merge swarms
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Environment: Any land or underground
Organization: Solitary (see below)
Treasure: None
GREATER CRANIUM RAT PACK
CR: 11
XP: 12,800
NE Tiny magical beast (extraplanar, swarm)
Init: +6; Senses: Darkvision 60 ft., low-light vision, scent; Perception +32
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AC: 27, touch 20, flat-footed 19 (+7 armor, +2 Dex, +6 dodge, +2 size)
hp: 143 (22 HD)
Fort +14, Ref +15, Will +10
Defensive Abilities: Psychic armor, reflexive dodge, swarm regeneration, swarm traits; Immune: Cold, weapon damage; SR 22
Weakness: Hive mind
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Speed: 15 ft., climb 15 ft., swim 15 ft.
Melee: Swarm (5d6)
Space: 10 ft.; Reach: 0 ft.
Special Attacks: Distraction (DC 22)
Spell-Like Abilities (CL 10th, concentration +14):
At will - Mind blast (60 ft. cone, Will DC 22 negates, stunned for 3d4 rounds, level 8)
Spells Known (CL 10th, concentration +14):
5th (3/day) - Hold monster (DC 21), mind thrust V (DC 19)
4th (6/day) - Lesser globe of invulnerability, mass pain strike (DC 18), telekinesis (DC 18)
3rd (7/day) - Clairaudience/clairvoyance, gaseous form, slow (DC 17), swarm of fangs
2nd (7/day) - Blur, daze monster (DC 18), knock, mirror image, resist energy, see invisibility
1st (7/day) - Charm person (DC 17), detect thoughts (DC 15), expeditious retreat, magic missile, psychic reading
0 (at will) - Dancing lights, daze (DC 16), detect magic, flare (DC 14), ghost sound (DC 14), mage hand, open/close, prestidigitation, read magic
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Str 2, Dex 15, Con 13, Int 19, Wis 13, Cha 19
Base Atk: +22; CMB: --; CMD: --
Feats: Combat Casting, Greater Spell Focus (enchantment), Greater Spell Penetration, Improved Initiative, Iron Will, Skill Focus (Perception), Spell Focus (enchantment), Spell PenetrationB
Skills: Acrobatics +27, Climb +10, Knowledge (arcana) +26, Knowledge (local) +26, Perception +32, Spellcraft +26, Stealth +31, Swim +11; Racial Modifiers: Uses Dex to modify Climb and Swim
Languages: Undercommon (can't speak); telepathy 100 ft.
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Environment: Any land or underground
Organization: Solitary, infestation (2-5 swarms), or plague (6-12 swarms)
Treasure: None
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Hive Mind (Ex): A cranium rat swarm has a hive mind, which makes it susceptible to mind-affecting spells. For the purposes of such spells, the swarm is a single creature of the magical beast type.
Merge Swarms (Ex): Two lesser cranium rat packs can move into the same space and merge into a single swarm, becoming an average pack. Likewise, two average packs can merge together into a greater pack. Merging in this fashion is a full-round action.
Although the packs consist of a greater number of creatures, the merged swarms pile up on top of each other and do not take up extra space.
Mind Blast (Sp): A cranium rat swarm can emit a powerful blast of pure mental energy that stuns all creatures within a 60-ft. cone. Creatures that fail a Will save against the mind blast are stunned. The save DC, length of time victims are stunned, and equivalent spell level are given in each swarm’s stat block. Cranium rats are immune to mind blasts from other creatures. This is a mind-affecting enchantment (compulsion) effect. The save DC is Charisma-based.
Psychic Armor (Su): An greater cranium rat pack mentally projects a protective field of force, granting it a +7 armor bonus to AC.
Reflexive Dodge (Ex): The constituent creatures of an average or greater cranium rat swarm can dodge attacks, forming holes in the swarm. It gains a +6 dodge bonus to its AC.
Spells: Average cranium rat packs cast psychic spells as 4th-level psychics, and greater cranium rat packs cast psychic spells as 10th-level psychics. They do not gain access to a discipline or other psychic abilities.
Swarm Regeneration (Ex): When a greater cranium rat pack is reduced to 0 hit points, it does not scatter. Instead, it becomes an average pack. Likewise, when an average pack is reduced to 0 hp, it becomes a lesser pack. When a lesser pack is reduced to 0 hp, it is destroyed. This transformation is instantaneous.
ENCOUNTERS WITH CRANIUM RATS
When designing encounters with cranium rats, remember that due to their merge swarm ability, multiple cranium rat packs can come together to form a swarm of much higher CR than your players are ready for. You may choose to ignore their merge swarm ability for the sake of building a lower-CR encounter.
Sorry for the long wait, Anon! Hope it's to your liking!
