Conduction

Lightning travels form your hand to the weapon you are holding. Make a melee spell attack against the target. On a hit, the target takes 1d8 lightning damage, and it can't take reactions until the start of its next turn and its movement is reduced by 10 ft  until the end of its next turn.

The spell's damage increases by 1d8 when you reach 5th level (2d8), 11th level (3d8), and 17th level (4d8).