Tooth fairy

The Tooth Fairy is an example of folklore mythology which adults know is fiction, but which is sometimes presented to children as fact. Another prominent example is Santa Claus. The realization or discovery that such stories are false is considered a part of the child's growing up. However many families participate in the roles of this myth even when the children are also aware of the fictionality of the supposed supernatural entity, as a form of play or tradition.

Typically, upon losing a tooth the child places the tooth under their pillow before going to sleep. In the morning they find a coin (or possibly a small bill) in the place of the tooth the next morning. In reality this is done by the child's parents or guardians.

The useful purpose of this myth is probably to give the child a small reward and something to look forward to when they lose a tooth, a process which the child might otherwise find worrysome.