You have a +3 bonus to attack and damage rolls made with this magic weapon.
Whenever you make take the Attack action and make an attack with the Bident of Thassa, you can make two attacks with the Bident of Thassa as a bonus action.
Once per day you may as an action speak the passphrase and throw the Bident of Thassa at an enemy, within thrown range. On a hit, the creaure's speed is reduced to 0 until it uses an action to remove the Bident from itself. Furthermore the Bident casts tsunami along it's path (DC23) and the creature hit by the throw automatically fails it's save.
3 times per day you can choose up to 3 creatures within 30 feet. These creatures must make a Will save. (DC 23) On a failure the creature will move to the closest enemy along the shortest route without harming itself, and attack. If their movement cannot get them to a creature they must dash towards the nearest creature. A creature will not move over obviously deadly terrain such as lava, or off of a cliff, but will move through brambles and spike growths in their rage. They continue to do this for 1 minute. At the end of each of the creature's turns it may repeat it's save ending the condition on a success.
You regain spent casts at dawn.
Proficiency with a trident allows you to add your proficiency bonus to the attack roll for any attack you make with it.
Notes: Bonus: Magic, Damage, Combat, Thrown, Versatile
Definitely a cool idea, but even before balancing specific mechanics it would be worth clarifying if this is intended for older editions of D&D because a DC23 saving throw is as good as saying "most creatures are going to fail this incredibly powerful ability" in 5th edition. A tip would be to look at items of comparable rarity in the DMG and look to the sorts of DC that are applied to effects like this. Also 5th ed doesn't do "Will" saves so clarifying whether you mean Int, Wis, or Cha would help.
Item probably deserves to be legendary or artifact rarity and almost certainly needs attunement requirements. Recharging abilities could have a 1d4-1 caveat, so that some days you might not recharge at all, making it less optimal to try using all charges every day.
Not entirely sure where the frenzied effect comes into the flavouring, but it seems more powerful than necessary. Consider reducing the number of affected creatures to 1, and also consider that in a lot of situations there may be a tie on how many creatures are "closest" for them to attack, so introducing tie-break clarity would be good. Also there is no clarity over when in the turn order/action economy the affected creatures move and attack - is this happening as you cast the effect? If so, you're giving 3 creatures a free movement and limited-use action out of turn; and if it's on their turn, it would be worth clarifying that if they aren't able to reach a creature within their movement, that they must use their action to dash instead of using it to attack. What of a creature that can do multiple actions or action types in their turn (do they have to use bonus actions to attack? If they have a bonus action that doesn't invoke an offensive action, can they use this anyway?), and what happens if the target changes over the course of their turn?
As I say, cool idea that just needs development and balancing!