Teostra

Flying, Blastblight, Fireblight, Menace
Supreme Ascension - Whenever Teostra destroys a creature put a Supreme counter on it, then if it has
5 or more Supreme counters on it you may transform Teostra.

{2}{r}{r}: Deal 4 damage to 2 creatures.

{6}{r}{r}: Deal 10 damage divided amongst 3 creatures.