Units in Erfworld - Known information

[glenndo]

It would say it's highly probable that the spidews have a poison special ability. Parson mentions it specifically as a special ability in his klog and I can't think of any other unit he could be talking about.

I believe you are correct since on page 26 he asks Tool if spidews are the same as spiders and specifically mentions poisonous bites as an attribute of the Earth Spider and gets a confirmation that spidews have the same ability.