Cessirid
Image by Thomas Baxa, © TSR, Inc.
[Dragon 150 has two articles about the illithids. One was a piece of fiction/ecology titled "The Sunset World", and the second was an installment of "The Dragon's Bestiary" focusing on natives of that planet, the illithidae. Three of the original monsters, the kigrid, embrac and saltor, were converted to D&D 3.5 in Lords of Madness. The fourth, the cessirid, was not.]
Cessirid CR 7 LE Aberration This creature looks something like a hyena, with a hunched back studded with two rows of short spines. Its head ends in a hooked beak, and four ribbon-like tentacles dance around its maw.
A cessirid is a pack-hunting carnivore found on planets terraformed by the mind flayers. They are sometimes called “illithid hounds” by adventurers, because illithids use the creatures as guard animals and trackers. Cessirids are rigid minded and very hierarchical. Every cessirid in a pack knows its place and how to challenge for leadership through contests of athletic prowess, and a lone cessirid is usually one that has been ejected from its pack, or is the sole survivor of a hunt gone wrong. Cessirid packs are very territorial, and clashes between packs, unless mediated by a more intelligent mind flayer, usually result in fatal violence.
Cessirids are well-versed in teamwork. They communicate with each other silently through telepathy while surrounding prey and setting up ambushes, and then strike in unison. They are as comfortable in the water as on land, and their ambushes may be from underground rivers or pools. A cessirid’s tentacles aren’t powerful enough to attack on their own, but secrete chemicals that cause incredible pain when smeared on an open wound (such as those inflicted by their shearing bites). Their magical abilities are used to position themselves, or to flee from a losing battle.
Cessirids lay their eggs inside of fresh corpses. They believe that the more intelligent a victim, the more cunning and skilled the young who grow up inside its carcass will be; this appears to just be a superstition. Cessirid larvae do not take over the tissues of the cadaver the way that illithid tadpoles do. Instead, they feed within the tissue until emerging as Tiny sized "puppies". Once emerged, the young are trained in the art of combat by the rest of their pack. Those that are hesitant towards violence are usually killed and eaten by their siblings.