Mirror, Mirror, On The Wall 

A young woman buys a mirror at an antique shop, and hangs it on 
her bathroom door. One evening, while getting undressed, she 
playfully says, "Mirror, mirror, on my door, make my bustline 
forty-four." 

Instantly, there is a brilliant flash of light, and her breasts 
grow to enormous proportions. Excitedly, she runs to tell her 
husband what happened, and in minutes they both return. 

This time the husband crosses his fingers and says, "Mirror, 
mirror, on the door, make my penis touch the floor!" 
Again, there's a bright flash... and his legs fall off!