Tidal FishhookWeapon 12
Source Pathfinder Lost Omens: Monsters of Myth
Damage 1d6 Piercing
Type Martial
Price 1,700 gp
Weight 1 bulk
This +2 greater striking returning Combat Grapnel takes the form of a fishhook made of scavenged bones and stone with a cord of braided water. Attacks with a tidal fishhook don't take any of the normal penalties for fighting underwater. A broken (but not destroyed) tidal fishhook can be fully repaired by submerging it in an ocean for 1 minute.
Activation 
Interact (teleportation, water)
Frequency once per hour
Effect A tidal fishhook can travel between bodies of water to strike distant foes. You throw the fishhook into a 5-foot square that's fully covered with water, and it emerges to Strike or Grapple a target from another such square within 60 feet; the squares can be part of the same body of water or different ones. The distance between the bodies of water doesn't count toward the fishhook's range increment. If you successfully Grapple the target as part of this Strike, you can pull yourself along the fishhook's line, teleporting to the secondary body of water.
Traits
This rarity indicates that a rules element is very difficult to find in the game world. A rare feat, spell, item or the like is available to players only if the GM decides to include it in the game, typically through discovery during play. Creatures with this trait are rare. They typically can't be summoned. The DC of Recall Knowledge checks related to these creatures is increased by 5.
FinesseYou can use your Dexterity modifier instead of your Strength modifier on attack rolls using this melee weapon. You still use your Strength modifier when calculating damage.
GrappleYou can use this weapon to Grapple with the Athletics skill even if you don't have a free hand. This uses the weapon's reach (if different from your own) and adds the weapon's item bonus to attack rolls as an item bonus to the Athletics check. If you critically fail a check to Grapple using the weapon, you can drop the weapon to take the effects of a failure instead of a critical failure.
TetheredThis weapon is attached to a length of rope or chain that allows you to retrieve it after it has left your hand. If you have a free hand while wielding this weapon, you can use an Interact action to pull the weapon back into your grasp after you have thrown it as a ranged attack or after it has been disarmed (unless it is being held by another creature).
ThrownYou can throw this weapon as a ranged attack. A thrown weapon adds your Strength modifier to damage just like a melee weapon does. When this trait appears on a melee weapon, it also includes the range increment.
TransmutationEffects and magic items with this trait are associated with the transmutation school of magic, typically changing something's form.
WaterEffects with the water trait either manipulate or conjure water. Those that manipulate water have no effect in an area without water. Creatures with this trait consist primarily of water or have a magical connection to the element.