Davy Jones' Key (Patreon)

Weapon (trident), legendary (requires attunement)

This powerful trident is made of verdigris-covered bronze. You gain a +1 bonus to attack and damage rolls made with this magic weapon. The bonus increase to +3 while you are underwater.

When you roll a 20 on an attack roll made with this weapon against a creature, that creature must succeed on a DC 15 Constitution saving throw or begin to suffocate. At the end of each of its turns, a creature suffocating in this way can make another Constitution saving throw. On a successful save or when it drops to 0 hit points, the creature can breathe again. A suffocating creature can't speak. A creature is immune to this effect if it doesn't need to breathe or has legendary actions.

Release the Kraken. You can use an action to speak the trident's command word to open a 15-foot-radius eldritch gate centered on a point you can see on the ground within 60 feet of you, turning the ground in the area into difficult terrain. If you are underwater, the point does not need to be on the ground. The gate is one-way. When the gate opens, up to 3 massive kraken tentacles appear through the gate, forcing any Large or smaller creature in the tentacle's space into the nearest unoccupied space. Each tentacle is treated as a Large monstrosity with 60 hit points, AC 18, a reach of 30 feet, immunity to all conditions, and a +7 bonus to all ability checks and saving throws. A tentacle can move anywhere within the gate's area on your turn (no action required) without provoking opportunity attacks. You can use your reaction to make an attack of opportunity with the tentacle. A tentacle remains until it falls to 0 hit points or the gate closes.

When the tentacles appear, they immediately make up to 3 melee attacks, one with each tentacle, against targets you can see within the tentacles' reach with an attack bonus of +10. On a hit, a target takes 3d6 bludgeoning damage, and if the target is Large or smaller, it is also grappled (escape DC 17). Until this grapple ends, the target is restrained. Each tentacle can grapple one target. A creature that ends its turn and is restrained by a tentacle takes 1d6 bludgeoning damage.

While at least one tentacle remains, you can use an action to repeat these attacks, making one with each tentacle. If an object is held or a creature is grappled by a tentacle, you can throw it up to 60 feet away in a random direction, knocking it prone, instead of attacking with the tentacle. If a thrown target strikes a solid surface, the target takes 1d6 bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 17 Dexterity saving throw or take the same damage and be knocked prone.

The gate stays open for 1 minute. It closes early if you dismiss it using a bonus action or if you drop to 0 hit points. Once this property of the trident has been used, it can't be used again until the next dawn.

My power runs deep. Deeper than the river, the sea, the ocean. I know it, for I've seen it. The pressure is enough to leave you breathless, and I alone have the key to harness it.