Adacthys
“14K” by Mark Hyzer, © Dementia 5 Publishing House, maybe. Accessed at the artist’s deviantArt here
[Sharks were to cartoons in the 1970s what apes were to comic books in the 1950s and 1960s. You wanna push product, put a shark in it. Hanna-Barbera was particularly shark happy, and humanoid shark men appear in multiple Scooby Doo series. They also got their own series with Jabberjaw, a cartoon in which the main character is a shapeshifting shark who talks like Curly Howard. He’s a drummer in a band in a futuristic aquatic society, and his response to the anti-shark racism of his world is to quip that he gets no respect like Rodney Dangerfield. To my younger readers, I assure you that every word in the last two sentences is 100% true.
The art above was intended for the Kaidan RPG, which never quite made it. In which case, I guess it’s supposed to be a samebito. The concept appears to have been sold to Rite Publishing, which put out a few modules and even a world guide for the setting for Pathfinder 1e, but never a monster book. If Dementia 5 Publishing ever put out a bestiary, they’ve successfully scrubbed it from the ‘net. Neither Paizo’s website or Drivethrurpg have evidence of it, and the Dementia 5 website is partially broken and contains listings of adventures only. So my best guess is that this and the other Japanese monsters done by the same artist were commissioned for a book that never got published. If anyone has more information, and knows if these ever saw print, I’d be very curious.
Lastly, this monster is canon in Pathfinder! The name and overall shape of the statblock are taken from Monster Codex, where this is listed as a variant sahuagin. I wanted to make an anthro shark a sahuagin-themed monster, and I noticed that Paizo had already done some of the work for me. Of course, my version has a few more tricks up its sleeve than the published outline...]
Adacthys CR 5 LE Monstrous Humanoid This immense creature looks like a vaguely humanoid shark. Its arms and legs end in clawed feet, and it has a short, lobed tail. It gazes appraisingly, hungrily, with beady eyes.
Adacthys are sometimes known as “prehistoric sahuagin”. They are throwbacks to a primeval age, larger and more physically shark-like than their kin. They are somewhat less intelligent and more impulsive than other sea devils, but compensate for this by both their physical size and increased magical powers. Adacthys can communicate telepathically with more than just sharks—other monstrous fish, aquatic reptiles and even primeval whales can fall under their influence. Adacthys can also shape water and conjure fog; these talents serve sahuagin raiding parties well when they move ashore.