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From Pathfinder Lost Omens Gods & Magic, which isn't enabled.

Rat-Catcher Trident

ITEM 11
Price 1200 gp
Usage held in 1 hand
Bulk 1
Category martial
Group spear
Damage 1d8 piercing

The haft of this +2 striking trident is carved with intricate designs of swarming rodents sacred to Hanspur, the drowned god of the Sellen River.

When used against a swarm, it ignores the swarm's resistance to piercing damage, if any.

Activate Interact
Frequency once per day

Effect While floating down a river on a raft or boat, you plunge the rat-catcher trident into the water. The trident casts a 5th-rank Control Water spell on the body of water.
Pathfinder Lost Omens Gods & MagicOGL