Quick idea i had for a new eidolon evolution:
Swarm (4 point-evolution):
An eidolon with this evolution becomes a swarm of tiny eidolons. The eidolons may differ in appearance, but all of them must display the same number of natural attack evolutions and the exact same visible other evolutions. strength, dexterity, natural armor and constitution are adjusted according to the size change. An eidolon swarm gains the swarm subtype and swarm traits. An eidolon swarm does not gain swarm attack damage dice according to its Hit Dice but instead its swarm attack deals 1d6 points of damage for each evolution granting the eidolon one or more natural attacks. Differently from other swarms you apply the eidolon swarm's strength modifier to the damage.
An eidolon swarm cannot take the Mount, Weapon Training, Large or Huge evolutions or any evolutions that are applied to one specific natural attack or a specific type of natural attack (sich as rend, grab, reach etc.). The eidolon swarm cannot be equipped with weapons or items of any kind (while individual creatures in the swarm may be able to wear or carry such items, they don't have any affect on the swarm), but if the summoner has the Aspect ability he can designate magic items he is wearing to apply to the eidolon instead of himself, while summoning the eidolon. This only works for non-armor items the summoner is wearing in magic item slots, not for weapons or slotless items.
For an additional 4 evolution points the eidolon swarm can be turned into a swarm of diminutive eidolons.
I'm sorry for erratic capitlization, punctuation and other things. I just needed to get this idea out of my system before i leave. Feel free to comment and critique.
I forgot to add, when the summoner fuses with the eidolon, the eidolon loses the swarm evolution for the duration, until the two split again.
Is there a level restriction to this evolution? Other than the 4 points it costs, that is.
no i originally thought it should be possible to have a swarm early on. Although i think the diminutive upgrade should be limited upwards.