Found and disciphered from a small, leather-bound journal located on a barrel in a storage room:
I have finally perfected my potion of rat domination. Unfortunately, the ingredients must be harvested from the fungus chamber, and it’s impossible to identify the deadly violet fungus hiding there. Many of my minions have perished collecting what I need.
My genius knows no bounds! My latest creation, the mighty rat-bear-pig, is a complete success. Its keen snout can safely sniff out the violet fungus so I can avoid them and collect my ingredients unharmed.
Potion of rat control ingredients: yellow puffball and weeping wig, both found in the fungus chamber. The ingredients are then distilled and mixed in my lab to create the potion. Don’t forget! Always forgetting! Damn that Old Voice’s buzzing!