Chatter’s final cry

The caster overloads their body with elemental energy, temporarily increasing their capabilities, but once the duration is over, they will erupt into a massive magical explosion. For one minute after casting, the user gains 120 feet of movement, a flight speed equal to their walking speed resistance to all forms of damage, 50 temporary hitpoints, and inability to be killed by a wish or power word: kill spell, once the duration is over, the caster’s body erupts into a massive blast of energy, dealing 10d20 force damage, plus 1d20 fire and radiant (d20 count halved rounded up in fires favor) for every level of spells slots the caster had remaining when this spell was cast (example: caster had 2 5th level spell slots, this spell would deal 10 d20 force, plus 5d20 fire and 5d20 radiant damage). All nonmagical items and terrain inside of the blast are destroyed. Any creatures killed are vaporized, unable to be revived by anything short of a wish spell. The caster is unable to be revived by any method. Any creatures and magic items caught in the blast (and survive) are launched 1000 feet horizontally away from the blast. If the caster were to die before the spell’s duration is finished, the user immediately explodes for half damage to everything within 500 feet.