Adapting Something From CoC D20- Need Help

[Hell_Born]

To make a long story short, there's a creature in Call of Cthulhu D20 that caught my attention recently. Called a "Worms that Walk", it's a Mage who cheated death by allowing himself to be consumed by worms and transferred his mind and soul into the swarm as they did so. The book also mentions variants called "Crawling Ones", who used different forms of vermin in the ritual. I'd like to run a game in Timor soon (after the Gazetteer gets done preferably) and I was thinking a Crawling One based around a swarm of either spiders or ants might be a good opponent.

There's three things I need; suggestions on how to actually create the Crawling One's stats by altering those of the Worms that Walk, suggestions on back history and suggestions on possible uses for it in the game.

[Nathan of the FoS]

For the stat conversion, I know that a "Worm that Walks" appears in the epic level handbook, and that Brandi did a version of the creature that's more suitable for Ravenloft encounters. I think it's in one of the QtR netbooks, but I'm not sure--Brandi?

[Brandi]

I don't think I ever submitted my WtW adaptation to a netbook.

Here's the link to my RTF file of the write-up, though. 'Fraid it's still done for 3.0, so it may need tweaking for 3.5. [ETA: in particular, the Swarm subtype didn't exist when I wrote this up originally]

[Hell_Born]

Thank you Brandi, though I'm a bit stumped on how to convert to 3.5. Could you suggest what alterations to make to a Crawling One made from Spiders? Or from Ants? Some advice on a potential backstory would also be greatly appreciated.

[Brandi]

Thank you Brandi, though I'm a bit stumped on how to convert to 3.5. Could you suggest what alterations to make to a Crawling One made from Spiders? Or from Ants? Some advice on a potential backstory would also be greatly appreciated.

I figure that unless the spiders or ants have a venomous attack, you could just declare it a special effect, so to speak (ie same stats, different looks). The biggest difference for 3.5 I could see is that you could opt to make them an Undead Swarm (which would alter the amount of damage they do and add some other effects), though when looking up the Swarm subtype effects in my 3.5 OGL, I noticed this:

Swarms made up of Diminutive or Fine creatures are susceptible to high winds such as that created by a gust of wind spell. For purposes of determining the effects of wind on a swarm, treat the swarm as a creature of the same size as its constituent creatures.

which I'm not sure I like, unless you just declare by fiat that the critter is made up of larger-than-average vermin (ie, at least Tiny size).

I should also disclaim at this point that I have never actually played D&D 3.0 or 3.5-- I had worked out some conversions to familiarize myself with the system, but I have a strong suspicion that if I ever organize my thoughts better a "Notes on GURPS Ravenloft" is going to be posted to my site someday.

As for creating a backstory... well, I suspect there's several folks here who can help you with that better than I can!