We're all grownups here...
A pretty simple one, but is open to HUGE amounts of creativity.
Pick a fairy tale (examples: Snow White, Jack and the Beanstalk, Little Red Riding Hood, etc) and tell it about the time you decided to appear in it. Out of nowhere -Whammy- you were in a fairy tale!
You can have fun with this, changing any number of elements with your presence. And make sure you mark it as mature if need be…