Shadowreaper Raven

Indetructible, Lifelink
When these creature comes into play, sacrifice all other creatures, you gain health equal to the total toughness of all creatures sacrificed this way.
{u}{u}{b}: Choose a Instant or Sorcery card from your graveyard, you may cast it without paying its mana cost. It gains Cascade and "Target player loses life equal to the converted mana cost of this spell"