There’s always going to be one player in every gaming group who rhapsodizes about the 1st or 2nd edition of the world’s oldest role-playing game. Give them what they want: Drop them into a pit of rot grubs.
The accident at Patchett Gulch forever changed the miners in Orvalt. Everyone knows the story—the cruelty of the overseers, the cave-in that trapped most of the men below, and then the tragedy: the dying purple worm that burst in on the trapped men, then began spewing rot grub swarms in its spasms. Every man who survived that day bears the scars from burning the rot grubs out of their bodies. But what most don’t know is that the worm revealed a seam of mithral and an entrance to the Realms Below. Now, in order to earn the right to mine the rare ore—or to pass Below (as some adventurers might wish to do)—the miners require all new hands to suffer a rot grub infestation and burn it out themselves.
A god of pestilence and parasites favored by evil giants protects his most ardent worshipers in the most disturbing way possible: He causes a rot grub swarm to grow in their guts. If the giant host falls to half hit points, the grubs burst out to attack the offending infidels.
Grubs are a good source of protein for hunter-gatherer tribes...making giant grubs are a great source. An alliance with the Sho-Shar can most easily be procured with the gift of a giant rot grub steak.
—Pathfinder Bestiary 2 215