Cage Lightning

You launch a lightning bolt toward a target you can see within range. Three bolts then leap from that target and surround him, caging it in an electric prison. The target must either destroy the prison or cross it taking 2d10 Lightning damage and fall prone.

The target makes a Dexterity saving throw, taking 10d8 Lightning damage on a failed save or half as much damage on a successful one.

Using a Higher-Level Spell Slot. One additional bolt leaps from the first target to another target (imprisoning only the first) for each spell slot level above 6.