Log Gar
The Log Gar is a fish from Lumberjack Folklore. It has saw-like teeth. They can cut through anything in the water and cut off limbs immediately. They will go through anything to kill prey.
Citations:
Bane, Theresa. Encyclopedia of Beasts and Monsters in Myth, Legend and Folklore. United States, McFarland, Incorporated, Publishers, 2016.
Rose, Carol. Giants Monsters and Dragons: An Encyclopedia Of Folklore Legend And Myth. United Kingdom, WW Norton, 2001.