My daughter lost a tooth last week and is old enough to know all about the "tooth fairy". Lucky for us, she still has enough kid magic in her to wonder and so she determined that with her new tooth in hand, she was going to find out.
(I can honestly tell her I'm NOT the tooth fairy. That really is her daddy's job.) After putting her tooth under her pillow for the night and reaffirming to her that I'm not the tooth fairy, I was fairly certain she had gone to sleep. Lack of noise, all that good stuff.
As my husband pushes open her bedroom door (it's older and sticks right at the beginning so you have to jerk it right at first) - it hits her cd player and then a loud cow bell starts clanking out. Ha ha! She made a trap for the tooth fairy! She put a ribbon with a cow bell on the door and her cd player right in the way to stop the door causing the loud cow bells to clatter.
The tooth fairy was lucky and complete his mission undetected - this time.