Knight Otu said:
If they can burrow through flesh, why not earth? Also, it improves their infiltration abilities. I'd highly recommend keeping it.
fair enough.
Knight Otu said:
As I originally envisioned them, they're also intelligent individually (though they sure cannot do alot individually).
how about this, then:
Hive Mind (Ex): Any nerve swimmer swarm with at least 1 hit point per Hit Die (or 12 points for a standard nerve swimmer swarm) forms a hive mind, and is treated as a single monster for the purposes of mind-affecting effects. When a nerve swimmer swarm is reduced below this hit point threshold, it cannot burrow into flesh or inhabit a host.
I wanted to tinker with the flavor text a bit, let me know if I’ve made any unpleasant/unnecessary changes (I didn’t remove any information – it just says the same thing with 44 fewer words):
A carpet of strange, small creatures crawls on the floor. It is hard to discern any details, on these miniscule wormlike creatures, though their bodies are partly split like a fork.
Nerve swimmers are horrors created by unscrupulous entities as instruments of torture and interrogation. They were derived from immature illithid tadpoles, but whether the illithids created them cannot be confirmed. Nerve swimmers burrow into the flesh and then the nerves of their victims, where they can easily control a host to do the bidding of the swarm’s master.
Nerve swimmers enjoy the tasks they were created for, but many swarms of nerve swimmers no longer have a master. These swarms often form their own agenda and act upon it. Being reasonably intelligent, they have taken to enslaving other creatures or simply recruiting them with the promise of reward. Among their favorite hosts are drow wizards, who usually lack the physical prowess to endure their tortures, but have enough authority and reputation to set the nerve swimmers' plans in motion.
While nerve swimmers are quite long-lived, regularly outliving their hosts, swarms without a host must hibernate for long periods. They may be placed in a large urn, but any environment will do. As the swarm hibernates, a few members die and spread their vital energy among the other members. Nerve swimmers cannot speak, but their telepathy allows them to communicate with most creatures.