Electric Field פ

Create a 15ft cube of lightning, harmful creatures inside must succeed a Con Save or take 2d10 lightning damage and loose their reactions, on a successful save the creature takes half damage and keeps their reaction. Whenever a creature enters or ends their turn in the cube they must make a Con save or take an additional 2d10 lightning damage and loose their reaction half on a successful save.

When casting the spell at 4th level or higher add 1d10 to the damage per level above 3rd level