From publisher blurb:
The Psionic Bestiary contains all manner of new creatures to unleash upon unsuspecting adventurers. In this release, we find six new monsters. Three of them, the brain worm, corpse beetle, and skull thrasher, are intertwined, while the other three, the azrathid, ghaar, and mathara tree, are separate, but interesting adversaries. These creatures range in CR, but all are ready for use in games that include psionic support!
In 2011, Dreamscarred Press held a contest for a psionic bestiary. The monsters from that contest are being released in a series of releases and will ultimately be compiled into a single psionic bestiary book.