The barbarian tribes of the far frozen north have long used a peculiar pickling method to detoxify shark flesh — they bury it in the sand to rot for months before digging it up again to air-dry. The resulting meat looks like tofu, feels like coarse rubber, smells like ammonia, and tastes like strong blue cheese — an acquired taste, but highly nutritious. A single shark can see an entire tribe through the worst of winter. At some point, a magical version of the dish calling for the addition of the pseudomagical mineral, chardalyn, began to circulate among the more isolated coastal tribes — especially those with sahuagin living just offshore of their territories.

One serving of this pickled shark meat provides enough nourishment to sustain a creature for one day. After eating a serving, you gain the following benefits for 8 hours.

• You have a swim speed equal to your walking speed.
• You can breath air and water, but you need to be submerged at least once every 4 hours to avoid suffocating.
• You have darkvision out to a range of 120 feet.
• You have advantage on melee attack rolls against any creature that doesn’t have all its hit points.

Curse. When you eat a serving of helvítis hákarl, you must make a DC 15 Charisma saving throw. On a failed save, you become charmed by Sekolah, the shark god, until the hákarl's benefits wear off.

While charmed in this way, the shark god casts suggestion on you at will (save DC 18), urging you to work toward the evil ends he desires.

Each time you are charmed by Sekolah in this way, roll a d20. On a roll of 1, you are permanently transformed into a sahuagin, and lose your sense of self. Only a wish spell can reverse this transformation.