Verion's Boltless Lightning

You unleash a pulse of blue electricity. Each creature in a 15-foot Cone originating from you makes a Constitution saving throw, taking 4d8 Lightning damage on a failed save or half as much damage on a successful one. A creature who failed the save cannot take a Reaction until your next turn as their muscles contract preventing quick movements.

Using a Higher-Level Spell Slot. The damage increases by 1d8 for each spell slot level above 2. The size of the Cone increases with the spell level. 2-3: 15-foot Cone, 4-5: 30- foot Cone, 6-7: 60-foot Cone, 8-9: 90-foot Cone.