After using grave digger to bring Liliana‘s Goliath back into play, I played the Lilianas Goliath. The mana was deducted from my crystals. And the card disappeared from my hand. But it never appeared on the field. Then next turn when I drew a card, the Lilianas goliath reappeared in my hand. But every time I tried to play it, it just went back into my hand.