Bluestone's Lightning Rod

A fluctuating stake of magnetic lightning attempts to impale a creature of the caster’s choice. The creature must make a dexterity saving throw or be staked cleanly by it. A creature takes 8d6 lightning damage on a failed save, or half as much damage and does not get impaled on a successful one.
When a creature is staked, it will uncontrollably attract electricity to it. When an attack that deals lightning damage targets this enemy, it will have disadvantage on the save, or the attacker has advantage on their attack roll.
The caster may also strike the ground with it, attracting and causing electricity to burst. When striking the stake with lightning damage, it causes a pulse of energy that deals half of that damage out to a radius of 15 ft. Creatures caught in the pulse must make a dex save.
The lightning rod ignites flammable objects if it is impaled into one.