Circuit Terrain

You transform the ground in a 20 foot square on the ground that you can see into shocking robotic circuits that shock anything they touch, this area counts as difficult terrain. 

When a creature enters the affected area for the first time on a turn or starts their turn there, the creature must succeed on a dexterity saving throw or take 3d6 lightning damage and get stunned for the next round, if a creature is already stunned, they take 3d6 more lightning damage but are not stunned again.