Since Mojang doesn't want to add sharks for some reasons after saying they don't fit Minecraft (why? there are dolphins, sea turtles, and tropical fish in Minecraft, so why not sharks?), so to replace sharks (other than the not-so-exciting drowned zombie variants), I think the original hostile aquatic mob should be added to fill the shark's role in Minecraft, the Sea Stalker. This mob would resemble a cross between a Plesiosaur, a Mosasaur, a Dunkleosteus, and a dolphin, but not too weird to be scary in the ocean. This mob should be about 6.5 blocks long, 2.5 blocks wide, and 3 blocks tall (including its fin). It should spawn only at nighttime when the seas become more dangerous, being filled with both hoards of drowneds and aggressive pods of sea stalkers. This mob should be able to destroy boats unlike most mobs, by attacking the boats from below in a manner similar to sharks. If this mob is added, this will likely make oceans more exciting and dangerous.
Mojang held a poll at Minecon Earth 2017 to let us decide which new mob would be added to the game, with the other three being permanently blacklisted. We chose Mob B, aka phantoms, but one of the other mobs was a giant squid-like mob that lived in the oceans. It would drag players underwater, but I don't recall if it was said it would attack boats. Anywho, because this idea is so close to one of the blacklisted mobs, I'm guessing it won't ever be implemented.
Not a bad idea. But I still think the best and the most natural options option would be adding sharks.
I don't understand why developers suddenly feel a strong social responsibility about sharks in the game, where you can do a lot of totally unrealistic or immoral things.
The player can destroy the walls of the house and the roof does not fall, massacre all creatures in the game, murder or enslave the villagers, but developers fear that adding sharks to the game can endanger sharks or children in the real world? This is one of the most stupid excuses I've ever heard.