Publisher's Website "This 17-page PDF presents a new monster for D20 campaigns, the possessors. An alien aberration that looks something like an octopus, possessors bite down over the heads of humanoids and use the bodies as a puppet.
This short PDF is a mix of artwork (14 sketches, 4 interior paintings, and the cover) and about 4,000 words of text. This is a very graphics-heavy PDF. This monster, all text and the visual appearance, is 100% open game content. While you cannot use the exact artwork in this PDF you can use the art as a guide and inspiration for creating your own."
The Possessors were created to provide a D20 Open Gaming compatible version of the D&D Mind Flayer, once it was revealed that the Mind Flayer and several other monsters were not going to be made Open Content in the final D20 SRD. Prior to this, the "gentleman's agreement" allowed such use.