Thousand Thunderbolts

"Heed the contract and serve me, O King of the Skies!
Come forth, Titan-slaying blazing thunder.
Hurl down lightning 100 times and even 1000 times!"

You rain down on the targets multiple pillars of fulminations.
10d12 lightning damage with advantage in a 32 ft/10 m range.
Targets are paralyzed. On a Critical, they also melt.