In Doubutsu no Mori and Animal Crossing, mushrooms are very rare and can only be found in the early morning from October 15 - 25, between the hours of 8 AM and 9 AM. At 8 AM, a mushroom will spawn and remain for 15 minutes, after which it de-spawns and another mushroom appears. Each mushroom is worth 5,000 Bells. Oddly, mushrooms are removed in the japanese release of Animal Crossing, and do not make another Japanese appearance until Doubutsu no Mori e+
In Animal Crossing: City Folk, there are five different types of mushrooms, appearing throughout the month of November. During November, six mushrooms will spawn throughout the town each day, appearing as either Flat, Round, Skinny, or Elegant. One of those six mushrooms will be a piece of the Mushroom Series disguised as a mushroom. If the town has attained perfect status, several of the six picked mushrooms may re-appear as a rare mushroom, buried underground. Players may either sell or eat mushrooms they find (and will blush if he or she eats a rare or elegant mushroom).
In Animal Crossing: New Leaf, mushrooms can be found near tree stumps. In addition to the five mushrooms found in City Folk is the new Famous Mushroom, valued at 16,000 Bells. Once eaten, the famous mushroom will cause the player to temporarily grow in a fashion similar to Mario eating a Super Mushroom from the Mario series of video games. The Rare Mushroom may only be found buried underground near trees and tree stumps once a perfect town rating has been earned.