Ill add the description you had on facebook for everyone here, because I thought it was super interesting.
"Not only are some species nearly euosocial, female Velvet spiders exhibit a remarkable type of maternal care among arachnids. Upon the birth of her brood, the mother spider liquefies her internal organs and regurgitates this material as food. Once her capability to liquefy her insides is exhausted, the young sense this and consume the mother. Now that's the ultimate sacrifice!"