Tiki's Tricky Thunderstorm.

At a point within range, dark clouds begin to appear and hail begins to fall, while lightning cracks and thunder rolls. Within a 30 ft radius of the point chosen, all creatures within that must make a Dexterity check or their speed is halved, if they fail by 10 or more they're knocked prone. On the casters action, they choose three points within the spells area for lighting to come crashing down. Enemies 5 ft from those points must make a Constitution save or suffer 4d10 lightning damage and become deafened. on a save they take half damage and keep their ability to hear. Each lightning radial effect must be next to another lightning strike. On a bonus action the caster can choose to move the point of the spells focus 30 ft, as long as the caster themselves don't move on their turn.

When cast at high er levels, the lightning damage increases by 1d10 per spell level.