Rumpelstilzchen

"Oh, how good it is that no one knows that I..." With these words, the little wretch dances around the fire, thinking that no one is listening to him.
For he once helped the poor miller's daughter to spin straw into gold and now he wants her first-born child as a reward. To prevent this, the queen and the king have to guess his name. Will they manage to guess his name and thus be able to keep their child?

Notes:
No age or size restrictions