I want to build an encounter similar to the one in Attack of the Clones, where kouhuns (the poisonous caterpillars that tried to kill Padme Amidala) attack the heroes. I imagine that they would be easy to kill (low wound threshold), but also very deadly.

How would you go about creating a creature with toxic venom? Would the damage increase over time as the poison travels through the PC's bloodstream? Would it create critical hit conditions which get progressively worse with time?

If anyone wants to take a stab at creating a stat block for a kouhun, I'd greatly appreciate it.

There are rules in the books for toxins. The Hutt book I'm pretty sure, Good starting point for how toxins mechanics are handled..

FFG is way ahead of you.

FFG is way ahead of you.

If you want to read the full FFG write-up on that, note that this creature is from the Force & Destiny CRB, on page 416.

Lords of Nal Hutta pg 109 and EotE Core 172 cover some basic poisons. I've also made creatures that spew acid, and done that by giving their natural weapon the Burn characteristic

I've taken some queues from the various poisons one could use in grenades or darts and modified to fit my personal taste. Here is a creature of my own creation. It is a reptomammal that hunts on a particular world a player & I created but will show up elsewhere in very rare circumstances.

FFG is way ahead of you.

Awesome, this is exactly what I was looking for. Thanks to everyone for the helpful tips!