Source: The End of Eternity, pg(s). 78-79
The coeurl resembles a big cat, only with hairless black skin, clusters of antennae instead of ears, and two spiked prehensile tentacles growing from its shoulders. Its forelegs are longer than its hind legs.
Coeurls are not native to Golarion, and are speculated to have arrived via portals between planets. They feed on an unidentified energy called id that they harvest from their prey.
A coeurl has blindsense out to sixty feet. It can corrode metal at a touch; also, by manipulating vibrations, it can work non-magical locks, disrupt machinery, and deal sonic damage to constructs. Coeurls are immune to sonic damage and resistant to electricity.
Although coeurls are intelligent and telepathic, they are not particularly communicative.