Mutfruit (Fallout 3)

Mutfruit is a food item found in Fallout 3. It can restore some of your Hit Points, but also gives you a small amount of radiation. They can be found by many traders in the Capital Wasteland such as Jenny Stahl of the Brass Lantern in Megaton and Gary Staley of Gary's Galley in Rivet City. Its structure is mainly a purple fruit that grows on a stalk, meaning that it would have grown on a tree. As the only living trees known present in the Capital Wasteland are in Oasis it is possible that they were grown here, though it is just as likely that it was created through genetic experimentation. Rivet City scientists are capable of growing fresh, radiation-free fruits and vegetables, so it's clear that fruit-growing climates can be replicated with the proper technology. There is no in-game description of the actual origin of the mutfruit.