Aaron, The Chosen Soul

Hexproof, Flying
Whenever Aaron, The Chosen Soul attacks, you may spend {u}{b}and sacrifice a creature, Aaron, the Chosen Soul gains indestructible and +X/+X until end of turn, where X is the power of the sacrificed creature
{1}{b}{w}{t} Exile target creature from your graveyard, Aaron, The Chosen Soul gains X +1/+1 counters, where X is the converted mana cost of the exiled creature