Magyck, Battle-Ready Sorcerer

When Magyck enters the battlefield with 4 Spell-Slot Counters.
When you use a Cast ability, remove a counter.
{x}{2}, {t}: Cast Delayed Fireball - Target up to 3 creatures a player controls. Deal x damage to each creature.
{6}, {t}: Cast Disintegrate - Target a creature. Deal 7 damage. If the creature is destroyed, exile it.
{3}, {t}: Firebolt - Place a level-up counter on Magyck. Deal damage where x is equal to the number of level up counters divided by 2, rounded down.