Erhenast the Passive

Flying
Erhenast the Passive can't attack unless you pay {3}, and can't block unless you discard a card.
{2}: Change a target of target spell or ability from a creature you control to Erhenast the Passive.
Whenever a Legendary creature you control dies, if it wasn't sacrificed, you may pay {1} and discard a card. If you do, Erhenast deals 3 damage to target creature or player.