Tooth fairy better pay EXTRA for this one ...
Here's video of retired U.S. Olympic athlete Bryan Clay -- who took gold in the decathlon in 2008 -- helping his daughter Ellie remove a loose tooth ... by tying it to a javelin!!!!
The footage is crazy ... Clay launches the javelin .. tooth goes flying out of Ellie's mouth ... then, blood.
By the way, MEGA PROPS to Ellie -- who's so tough, she not only DIDN'T cry ... but only asked for a glass of water to wash out her mouth!!!