Trail of Cthulhu: Eternal Lies
In the unnamed temple in Dallol which also held a growing Major Mouth, the investigators encountered several torsos hanging from the ceiling. The torsos were scarred, tattooed and painted with strange sigils which Prof. Marvin Derrikson determined were sacred and secret formulas for creating a Major Mouth. These profane instructions would allow several people to perform horrific acts of depravity which would help nurture and grow the abomination.
While not something the investigators were interested in enacting, the knowledge would no doubt be useful in future investigations.