Xena, Tomb-Warden

Flying, indestructible, lifelink
if a creature would be exiled for any reason, it is destroyed instead.
If a card would be put into exile for any reason,
reveal it and put it into its owner's graveyard
instead.
Any player may pay x life to prevent these effects
where x is the converted mana cost of the
revealed card.
Xena's toughness is equal to the total number of creature cards in all graveyards.