The Obscured Ghost with Tentacles is an entity who was trapped and placed in the Containment Unit.
The Obscured Ghost appeared to prefer underwater environments and occupied an area of the containment universe flanked by a waterfall. After he was stranded in the Containment Unit during the Fenris case, Slimer was surrounded by the Maggot Ghosts then grabbed by the Obscured Ghost. It pulled Slimer underwater but lost hold of him. It later encountered Eduardo Rivera but ejected him from his domain.