Tempest Cloak

Those who wear this cloak are protected from the
sky's wrath and have resistance to Lightning
damage.
When attuned the wearer may, once per day as a
bonus action, turn into living lightning. While in
this form they gain resistance to all damage until
the endof their next turn. Additionally all damage
dealt by attacks are turned into lightning damage,
and at the endof any movement deal 3d10
lightning damage to all creatures within 5 feet.