demiurge1138
Inventor of Super-Toast
Looks pretty good to me. I was going to suggest negative energy for the web from the original text, but it then specified that it was, in fact, cold damage.
Since the web glows green, shouldn't the Spot DC be a little lower than 20 (which is from the normal monstrous spider)?
As such, phantom spiders are partially immaterial, and easily fade into the darkness, except when they are arroused, their bodies are suffused with a cold witchlight while their eyes gleam with hellish malice.
We could either do that or do our own wraith spiders and put a note that advanced phantom spiders become wraith spiders. What do you think? Sounds like the CotSQ wraith spiders are duds, so I'd be up for converting those.