Plague Moth

Plague moths are enormous gray moths with glowing green eyes, the botched result of a wizard's plan to grow potions 'naturally'. They brew faulty draughts and crave blood like stirges, but it is their venom, not their bite, that kills, and it kills in lurid ways.

They hunt in large swarms, but at most three moths attack one creature; the rest find other prey. They are nimble and nearly immune to magic. Roll a random potion on the standard table for each moth's venom; results of healing, oils of every kind, and anything worth 300 XP or more instead become a potion of delusion that mimics a helpful draught such as giant strength or extra healing. Bites from more than one moth call for a roll on the potion compatibility table, ignoring the rule that delusion mixes safely with anything. Moths are immune to each other's venom, and unlike stirges they usually wait for prey to die before feeding.

Swarms spend half their time dormant and half hunting. Underground, darkness and daylight are all one to them, but the few that have surfaced hunted only at night.

Attacking nearly anything alive, they disrupt the food chain, yet their frailty keeps them from overrunning the sewers. Smarter sewer dwellers have learned never to eat one. Captives quickly wither and die, so no one has managed to harvest their potions.