Wanted: Bugs, The icky paracritter kind Options

[Blaze]

In a usual case of plotline being written without consulting the sourcebooks, I've hit a point in my next planned game where I need a nasty awakened insectoid paracritter that's likely to live underground, but don't know which to use, or even if there is one that fits the bill. I'm looking for something nasty enough to give hardened combat characters pause, but feeble enough that I can use a swarm of them without my players getting geeked before I'm done with them. Ideally some sort of large spider would fit the bill, but as one of the players is chronically arachnophobic, that's forbidden territory. Is there anything I can use for this situation (think Indiana Jones meets Resident Evil), or am I going to have to rewrite that bit and go with the old classic zombies?

-JH.