Invasion of Ulgrotha // Grandmother Ravi Sengir

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Ulgrotha enters the battlefield, it deals 3 damage to any other target and you gain 3 life.
Flying
Whenever a creature an opponent controls dies, put a +1/+1 counter on Grandmother Ravi Sengir and you gain 1 life.