The entity has a full range of animations and appears in several map files and scripts, but I don't remember seeing him anywhere except as a corpse in Omicron. Maybe the corpse was originally supposed to spring to life, but for whatever reason it didn't make the final cut.
He's mentioned in these portions of the 03_02_omicron_inside.hps map file; maybe a scripter can understand what was supposed to happen with him: