Fungus Deal

 refers to an unmarked and repeatable quest in Fallout 3.

Talking with Eclair, Little Lamplight's cook, reveals that he is in need of Strange Meat. He explains that there is a fungus which grows in the cavern's pools which makes up an important portion of the children's food supply. This fungus seems to thrive on meat, especially Strange Meat, a discovery the first children of Little Lamplight made when they threw the bodies of dead adults into the pools. Lucy, Little Lamplight's medic needs Buffout, from which she can derive a useful treatment for the rickets Little Lamplighters are subject to due to malnutrition and lack of exposure to the sun.

Although the player must get Mayor MacCready to agree to it, Eclair and Lucy will both trade one unit of Cave Fungus for three units of Strange Meat or Buffout, respectively. With the Child at Heart perk, the cost is lowered to one unit per fungus cube. The fungus removes a small amount of radiation in addition to healing the player.