The Houndgar (Teuthis courser, dev nickname “hunting dog squid”) is small, but dangerous out of proportion to its size because of who it hunts with. It is the spotter in a symbiotic pair: it finds and corners prey, the Marrowbreach delivers the kill, and the Houndgar feeds on the scraps.
Its eight chromatophore-covered arms perform motion-camouflage displays on approach, then produce a sudden bright flash to dazzle prey — opening the window for a Marrowbreach strike. The reward structure (“the bigger the prey, the more the Houndgar benefits”) is theorised to push Marrowbreaches toward larger targets over evolutionary time.
Counterplay: the flash is an explicit tell. Any Houndgar dazzle means a Marrowbreach attack is imminent — break off and take cover immediately. The wiki notes they may be intelligent and “perhaps trainable.”