Penance egg

A Penance egg is used to color a whip white in the rewards of Barbarian Assault. This is proven from the examine text: A weapon from the abyss painted white from the yolk of a penance egg. This could kind of be considered an item, even though it is unobtainable, and can never be seen.

Penance eggs would come from the queen even though you can never see it laying eggs.