Brainiac rat swarms and gestalts have a hive mind, which makes them susceptible to mind-affecting spells. For the purposes of such spells, the swarm or gestalt is considered a single magical beast.
As a standard action, Brainiac rats can link their minds to form a swarm, or join a previously existing swarm or gestalt. Upon doing so, the merging party loses any remaining actions and ceases to be a separate entity. If the amount of rats in a swarm or gestalt hits a certain size threshold, it instantly becomes the new size.
| Minimum Threshhold | Size |
|---|---|
| 10 | Minor Swarm |
| 40 | Lesser Swarm |
| 50 | Small Gestalt |
| 160 | Swarm |
| 200 | Medium Gestalt |
| 640 | Greater Swarm |
| 800 | Large Gestalt |
| 2560 | Superior Swarm |
| 3200 | Huge Gestalt |
A brainiac rat swarm or gestalt can separate some of its rats to create new swarms and/or reduce its size. Up to 10 rats can be released as a free action. A minor or lesser swarm can be released as a move action. A swarm can be released as a standard action. Larger swarms can only be released as a full-round action.
If the number of rats released lowers a swarm or gestalt below its size threshold (see marge above), it immediately becomes the new size. The newly released rats or swarm spawn next to the parent swarm or gestalt. If the parent drops in size, the new rats or swarm must spawn in a space previously occupied by the parent swarm.
The new rats or swarm roll initiative at the start of the next round of combat. They are not considered flat-footed, but they cannot take attacks of opportunity until their first action.
Brainiac rats can cast helping hand as a spell-like ability once per day. When they do, the "hand" takes the form of a ghostly rat.
Brainiac rats have a +5 circumstance bonus on Perception checks; this circumstance bonus increases to a +10 circumstance bonus on Perception checks to find invisible creatures or objects, incorporeal creatures or objects, or things that exist only on the Ethereal Plane.
As a full-round action, brainiac rats can send out a telepathic SOS to other brainiac rats in the area. A call can reach other brainiac rats within 400ft + 40ft per caster level. This distance is given in the statblocks above.
Brainiac rats can respond to another rat's call reinforcements by using their dimension door ability as an immediate action, appearing by the calling rat's side. The calling rat must be within the receiving rat's ability range. The rat, swarm or gestalt appears just before the start of the caller's turn. If enough rats are present, they automatically form a swarm of the appropriate size and can act immediately. If more than one is present, the swarm or gestalt with the most hit points takes primacy.
If the receiving rat is out of range or otherwise cannot respond immediately, the rat remembers the location of the call for 1 minute and can dimension door there as normal, though they must wait until their next turn to attempt to merge with the caller.
When a gestalt or swarm of sufficient size forms, it may choose to swap out some or all of its Focus or Spell-Like Ability feats for any others on this list: Ability Focus, Bouncing Spell-Like Ability, Reach Spell-Like Ability, Spell Focus and Greater Spell Focus. The new feat may target a different ability or school of magic.
The chosen feat remains with the swarm or gestalt until it disbands. If it increases in size, it can swap out newly gained feats, but cannot swap out a feat it already swapped or accepted as-is.
A swarm of sufficient size can transform itself into a gestalt, appearing to coallesce into a single being made up of dozens of indivudual rats acting as muscles, bones and so forth. This gestalt typically takes the form of a ratfolk, though it can take any appropriate-sized form it chooses. The gestalt is capable of speech, though it's voice a bit halting and raspy.
Forming a gestalt is a full-round action that provokes attacks of opportunity. They are still considered a swarm until the process is complete, at which point they lose the swarm subtype and are treated as a single magical beast.
| Starting Swarm | Number of Rats | Gestalt |
|---|---|---|
| Lesser Swarm or Swarm | 50-199 | Small Gestalt |
| Swarm or Greater Swarm | 200-799 | Medium Gestalt |
| Greater or Superior Swarm | 800-3199 | Large Gestalt |
| Superior Swarm | 3200+ | Huge Gestalt |
An opponent that grapples or is grappled by a gestalt automatically takes damage equal to the gestalt's slam attack, as the constituent rats bite and claw in defense. This is a piercing and slashing attack that happens at the start of the gestalt's turn.
A swarm or gestalt that is reduced to zero hit points does not automatically die. Instead, it changes into a swarm or gestalt of the next lower size with its full amount of hit points. The number of rats composing it drops to the halfway point of the new size.
If more damage is dealt to the swarm/gestalt than it has hit points, the excess damage is applied to the new, smaller group. (This may cause it to drop yet another size, which continues the process.)
A gestalt reduced this way can opt to reduce to a swarm instead of the next gestalt down, but a swarm cannot reduce into a gestalt. A small gestalt is always reduced to a lesser swarm at 0hp, and a minor swarm reduced to 0hp turns into 1d4+1 individual rats with no excess damage applied to them.
| Starting Size | New Size | Rats Contained |
|---|---|---|
| Huge Gestalt | Superior Swarm | 2880 |
| Large Gestalt | 2000 | |
| Superior Swarm | Greater Swarm | 1600 |
| Large Gestalt | Greater Swarm | 720 |
| Medium Gestalt | 500 | |
| Greater Swarm | Swarm | 400 |
| Medium Gestalt | Swarm | 180 |
| Small Gestalt | 125 | |
| Swarm | Lesser Swarm | 100 |
| Small Gestalt | ||
| Lesser Swarm | Minor Swarm | 25 |
| Minor Swarm | 1d4+1 brainiac rats | |
The constituent rats in a swarm can jump out of the way of incoming attacks, forming holes in the mass. They have a +4 dodge bonus to AC.
As a standard action, a gestalt or swarm can emit a wave of pure mental energy in a 60ft cone. Targets caught in the blast must make a Will save or gain a negative status condition. The base DC is Charisma-based and is given in the stat block, and is modified according to the condition chosen. This condition is chosen by the swarm/gestalt when it makes this attack; it can't choose different conditions for different targets.
| Condition | Duration | DC Mod |
|---|---|---|
| Shaken | 1 minute | +2 |
| Frightened | 1d6 rounds | +0 |
| Panicked | 1d4 rounds | -2 |
| Cowering | 1d4 rounds | -2 |
| Sickened | 1 minute | +2 |
| Staggered | 1d6 rounds | +0 |
| Stunned | 1d4 rounds | -2 |
| Confused | 1d4 rounds | -2 |
This is a mind-affecting enchantment effect. If the chosen condition is shaken, frightened, panicked or cowering, it is also a fear effect.
Brainiac rats are immune to all mind blasts.
The gestalt or swarm has enough power and focus to mentally create a physical barrier between it and its enemies. This provides a +7 armor bonus, and is a force effect.
The gestalt's slam attacks are enhanced by the potency of their mental focus. Their base damage is one step higher than their size would indicate, and they add their Intelligence bonus to damage dealt. These attacks are considered to be force effects for purposes of hitting ethereal creatures and the like.
A gestalt can cast spells as a psychic. Its caster level and spell splots are determined by its size.
| Size | CL | Spell slots per day | ||||||
|---|---|---|---|---|---|---|---|---|
| 1st | 2nd | 3rd | 4th | 5th | 6th | 7th | ||
| Small | 9 | 6 | 6 | 5 | 3 | — | — | — |
| Medium | 11 | 6 | 6 | 6 | 5 | 3 | — | — |
| Large | 13 | 6 | 6 | 6 | 6 | 5 | 3 | — |
| Huge | 15 | 6 | 6 | 6 | 6 | 6 | 5 | 3 |
Owing to the diverse talents of brainiac rats, each gestalt has access to slightly more spells known than a psychic of an equivalent level.
| Size | Spells known | |||||||
|---|---|---|---|---|---|---|---|---|
| 0th | 1st | 2nd | 3rd | 4th | 5th | 6th | 7th | |
| Small | 9 | 6 | 5 | 4 | 3 | — | — | — |
| Medium | 9 | 6 | 6 | 5 | 4 | 3 | — | — |
| Large | 9 | 6 | 6 | 6 | 5 | 4 | 3 | — |
| Huge | 9 | 6 | 6 | 6 | 6 | 5 | 4 | 3 |
Upon forming, a gestalt "learns" its spells. You can choose these yourself or determine them randomly from the suggested list below:
A gestalt's primary spellcasting ability is Charisma. Medium gestalts and larger have Spell Focus (enchantment) by default, increasing enchantment spells' DCs by +1.
| Size | Spell DCs | |||||||
|---|---|---|---|---|---|---|---|---|
| 0th | 1st | 2nd | 3rd | 4th | 5th | 6th | 7th | |
| Small | 13 | 14 | 15 | 16 | 17 | — | — | — |
| Medium | 15 | 16 | 17 | 18 | 19 | 20 | — | — |
| Large | 17 | 18 | 19 | 20 | 21 | 22 | 23 | — |
| Huge | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 |
A gestalt that increases size keeps its currently known spells and adds new ones. A gestalt that shrinks in size "forgets" spells, but re-learns the same spells if it increases in size later.
Upon increasing in size, if the gestalt has used some of its spell slots, it re-gains access to one spell slot of each level it can cast. Upon reduction in size, spell slots already cast are lost before other spell slots.
If a gestalt collapses into a swarm then reforms later, its collection of spells "known" may change, but the status of its spell slots are not.
Whenever a gestalt casts a spell or uses a spell-like ability with a range of touch, it may release a single brainiac rat to deliver the touch. This is a free action, and the rat acts immediately after the gestalt, and its touch attack in that round is a free action. If the attack misses, the rat can continue to attempt to deliver the spell, but must do so as part of a normal attack.
Alternately, the gestalt can throw the brainiac rat as a move action. Use the gestalt's base attack bonus plus its dexterity modifier to make a ranged touch attack. This attack has a 20ft range increment for a small gestalt and increases by 20ft for every size category above that. On success, the spell is delivered, and on failure the spell is lost. In either case, the thrown rat takes 1d6 fall damage for every range increment it is thrown. It can make a DC 16 Reflex save to only take half damage.
A gestalt cannot use split and deliver touch spell by proxy in the same round.
A gestalt is immune to precision damage (like sneak attacks) and has a 50% chance to negate any critical hits confirmed against it. It also has a +5 bonus to its CMD when resisting the dirty trick, grapple and trip maneuvers.
Despite having a clearly formed "front" and "back", a gestalt's component rats can still see in all directions. As a free action on anyone's turn, a gestalt can supress this ability and focus only on its "front". It can re-enable the ability as a swift action on its turn.
Somewhat larger than normal rats, brainiac rats have sleek black or dark gray fur. Their eyes are a piercing blue, set in heads that look slightly too big for their body.
Brainiac rats prefer their own company to that of others, as it's much easier to communicate in a hive mind than verbally or even telepathically. Still, their thirst for knowledge often drives them into contact with beings, forming gestalts and using spells like adjustable disguise to walk secretly among the "normal" races. A typical disguise usually involves some sort of scarred throat, as a gestalt's speaking voice is quite coarse and raspy.
Brainiac rats prefer to avoid combat, using dimension door to escape early. If pressed, they will call reinforcements and focus on their mind blast and touch of mercy abilities to render the toughest combatants less of a threat while they form gestalt and unleash their spellcasting abilities.