I may have found something. A rare substance in the sewers.
It has the ability to make one hallucinate. More importantly, it is mutagenic and enhances creatures that undergo a certain process. The subject is granted the ability to spray acid and vomit forth a roiling mass of diseased fluids.
There is a machine responsible for this, built over a body of sludgey green fluid. It may be that Ytthx'tnssp'pssph lays very near to this region. If you know of any way to awaken, communicate, or even tempt the Elder back to where It belongs I will need to know soon.
M.D.
------------ I'd love to find a DM willing to take Mandarin and a party SCUBA diving tomorrow night EST to see if I'm right.