Crown of Storms

Gain advantage on saving throws against being
frightened, charmed, and thunder and lightning.
Once a day, as a bonus action, you may activate
the crown and gain the following for 1 minute:
{1} Flying speed of 30 ft. and able to hover
{2} Swimming speed of 30 ft. and water breathing
{3} When you roll a 20 on your attack roll, you
may slow your target for one turn, halving their
speed, giving them disadvantage on their next
attack roll, and they can't use reactions.
Requires Attunement.