Vyvyan Basterd
Adventurer
kigmatzomat said:The swarms don't overlap because the swarms would be crowded in that overlap. They essentially refuse to pack in less space or crawl over each other; the exception is that they will crawl over things that they need to kill, hence targets do not count for against the overlap.
Where does it say this in the RAW? The SRD says that "It can occupy the same space as a creature of any size, since it crawls all over its prey..." It does not limit that the other creature cannot be a swarm.