Chaos Shaping in Limbo
Right now, I'm writing up the slaadi for my GURPS Monstrous Compendium, but to do it properly, one has to explore how the plane of Limbo works in D&D and how to adapt the mechanics to GURPS. This is not going to be simple. What you see is a combination of the mechanics from the Planes of Chaos 2e boxed set and Manual of the Planes 3e book.
I'll note that some effects are intentionally left vague because I don't feel like going into too much detail right now - I just have to get the basics covered to be able to progress.