Wereshark
From Ardrana
The wereshark is an avaricious hybrid of man and shark, These huge predators destroy large caches of fish (and fishermen) and have been known to attack nearly any form of aquatic life, including the intelligent races such as tritons, sea Elves, and merfolk.
Human weresharks are primarily solitary creatures in either form. Occasionally, they might cooperate on a limited basis with each other, with sahuagin, or with priests of various evil sea gods, but these instances are quite rare. Weresharks are, first and foremost, individualists out for their own gain.
The wereshark is a huge, muscular brute when in human form, tending to use their inordinate strength to savagely attack people hand-to-hand, able to rip an arm off grappled opponents. In human form, weresharks can breathe underwater for one hour. Cruel and arrogant in its human form, a wereshark is even more vicious in its shark form, that of a great white shark.
The wereshark typically has an entourage of several common sharks, which attack in concert with the wereshark. In heavily shark-infested waters, the scent of blood often brings swarms of sharks and whips them into a feeding frenzy. Weresharks, out of cruelty, often make passing attacks at victims simply to entice other sharks into attacking them while it waits to collect any treasures, such as magical weapons and items.
Weresharks in human form tend to be maimed in some way (missing limb, eye, severe scars, or other disfigurement), though these marks are not evident when they are in shark form. Weresharks are fiercely territorial, staking claims on sunken ships or undersea caves and defending them to the death. They often plunder these areas so they can use the treasures found for their own gain above the waves.
There are also persistent rumors among the sea-dwellers of sahuagin weresharks that are unholy warriors and are larger than any known human weresharks.
Note: Weresharks originally appeared in this form in the Monstrous Compendium Annual Volume 2 for the AD&D game from TSR. Their use here is for the purposes of providing context for the campaign only.