It's a Kamadan.
did I miss the source? where did this information come from?
(I mean, I know Perkins...but where)
My OP got edited and much improved by a mod. It links to a tweet from Perkins.
Ah, but Slaadi are intellectual wotc property... and they haven't been the focus of much attention in the past. Plus, they're pretty easy to write big adventures around, and they have ties to a lot of things that are SO D&D - Modrons, for example, as well as many planar monsters like Githyanki.
Undead and Giants are pretty much Paizo's territory right now, and they're sort of played out. Slaadi would be interesting, new, and yet still close enough to "core" D&D that it's not a huge risk. Anyways, it's my guess at least.