Geppetto's little wooden creation come to life, Pinocchio, would cause a paradox if he said "My nose will grow now".

As Disney explains to us, Pinocchio's nose grows when he tells a lie.

If he were to say 'my nose will grow now' and his nose does grow, that would mean he wasn't lying. But if he wasn't lying his nose would not grow. But at that point his statement would be a lie so his nose would grow... But then it would not be a lie so his nose would not grow, and on and on and on...

So in reality his nose would have to grow in order to make his statement not a lie, but it cannot grow otherwise it would not be a lie.