Choso

Flowing Red Scale - {x}{x}{b/r}, {t}: Put X +1/+1 counters on up to any amount of black or red creatures you control, then sacrifice a
nontoken creature you control and double the amount of +1/+1 counters on Choso.

Supernova - Remove 3 +1/+1 counters: Deal 2 damage to each creature you don't control.