Tempest Current

You conjure a roiling current of misty seawater threaded with pale blue lightning in a 20-foot-radius sphere centred on a point you can see. When the spell is cast, and whenever a creature enters the area for the first time on a turn or starts its turn there, it must make a Dexterity saving throw.

On a failed save, it takes 2d6 lightning damage and 2d6 cold damage, and becomes soaked until the start of its next turn. On a success, it takes half damage and isn't soaked.

Soaked

A Soaked creature suffers the following effects:

• Its speed is reduced by 10 feet.
• The first time each round it takes lightning damage, it takes an additional 1d4 lightning damage.
• If another Soaked creature is within 10 feet, lightning arcs between them. That second creature takes 1d4 lightning damage (no action required). Each creature can only be hit by one arc per turn.

Tide Cascade

Whenever a creature drops to 0 hit points while Soaked, the water violently surges outward.

Choose another creature within 20 feet of it. That creature immediately becomes Soaked and takes 2d4 lightning damage.