Fungus Deal

Fungus Deal is a repeatable quest in Fallout 3.

Synopsis
By some miracle, Little Lamplight continues to survive despite the ever-encroaching wasteland, however, not without difficulty. One of the most important problems is the lack of resources for making cures for various diseases, such as rickets, caused by malnutrition. Another is the constant shortage of foodstuffs. The children improvise various treatments and foodstuffs from available materials. The Lone Wanderer can lend a hand!

Walkthrough

 * This repeatable quest allows the player to trade items in to Lucy or Eclair in return for cave fungus.
 * Lucy will take Buffout, providing one piece of cave fungus for every three bottles of Buffout.
 * Eclair will accept strange meat, providing one portion of cave fungus for every three portions of strange meat. It's actually human flesh, used as fertilizer for the kids' fungal colonies, first discovered after they dumped adults' bodies in them.
 * To unlock this functionality, the player needs to talk to Mayor MacCready and get him to approve the deal, with either 50 Barter or the Child at Heart perk. Note that threatening MacCready at any point to gain 10 pieces of cave fungus will permanently disable the ability to trade for it.
 * The deal can be (re)negotiated with higher barter, so that the kids will provide one portion of cave fungus for every two items traded in. This requires 75 Barter and can be attempted at any point, even after the trade deal is accepted.