Tl;dr: Flying serpent that bites the masts, breathes fire.
It's been more than 2 years since Rare added a randomly spawning PVE threat to the seas, and since then they've added plenty of new mechanics that could be utilized by a new monster.
Enter the Leviathan!
Appearance- a long serpent that can fly. Something in the vein of how dragons are depicted in south-east Asian cultures, or the Mayan Kukulkan.
What's it do?- the leviathan primarily flies in a wide circle around your ship (similar to a meg) before eventually performing one of three actions:
- Dives into the water, causing it to boil. It's head emerges 5-10 seconds later and, after a short delay, shoots a fireball at the side of your ship. The fireball would inflict 2 mid-sized holes on each level hit (e.g. just 2 on a sloop or brig, but 4 total on a galleon), and knock any nearby pirates away, potentially into the boiling sea. It would also start a fire at the base of each hole, although this fire will be quickly extinguished if water is pouring in. This attack can be prevented if you shoot it enough times with the cannons The leviathan will then resume it's circling pattern in the sky.
- Bites the top of one of the masts, and starts tugging/pulling on it. Will cause 1 unit of damage after 5-10 seconds of chewing. No matter which mast is targeted, part of the body always remains target-able by the cannons. Will stop if shot enough times, or if the mast is broken.
- Hovers over the ship for 5-10 seconds, then breathes fire downward, setting a large area on the top deck on fire (but causes no outright damage). Can be stopped if shot enough times, but unlike the previous two attacks, it's body might not be in a position for the cannons to target.
All of these attacks use pre-existing game mechanics. Biting the mast is similar to the kraken wrapping the ship, Firebreath from ashen winds skull, Fireball and boiling seas from volcanoes, Circling pattern from Meg, head emerging from sea like the kraken, etc.
How is this encounter different from all the others?- Unlike the other randomly spawning threats (kraken, meg, and skelly ship), the leviathan focuses more on setting your ship on fire and crippling it, rather than damaging it outright. It also flies, which gives pirates a rare reason to point their cannons upwards. Unlike the kraken and skelly ships, you can escape it by sailing to an island, although you're rewarded with plenty of loot if you kill it instead. Speaking of, it also offers a unique method of killing it: if you have a bunch of gunpowder in your crows nest, you can detonate all of them when the leviathan is close (such as when biting the main mast, or preparing to use firebreath) to cause a lot of damage!
Lore?- Flameheart summons it. There's even a ship set called the ashen dragon that could be a reference to it.
What do you think?