The Mushroom House is the home for the tooth fairy in Stampy's Lovely World. Stampy left it there so the fairy may live there the fairy is the Tooth fairy, it was built as a joke by a helper but soon became useful for the Tooth Fairy, but the Tooth Fairy moved out to somewhere else, it is likely that she has made a new hosue.
Building
When Stampy built Harrison's home he seen it and left it alone because the Tooth Fairy needs sleep.