Aurelion Sol, Star Forger

+2: Create a 1/3 Star creature token with defender and "Whenever this creature dies Aurelion Sol, Star Forger loses 1 loyalty."
0: Aurelion Sol, Star Forger becomes an X+1/X+1 legendary dragon with flying until end of turn, where X is the number of Star tokens you control.
-7: Sacrifice all Star tokens you control, then deal 2 damage to any target for each one sacrificed this way"