Giant Octopus

The Giant Octopus, not to be confused with its very real counterpart the giant squid, is a creature of myth. As long as humans have stared out into the depths of the ocean, dwellers of the deep have captured the collective imaginations of mankind. To that end, we often deploy creatures like the Giant Octopus in a similar manner to how one might use a Kraken; something in the seawater to be feared and talked about by sailors and fishmongers.

While I think there are plenty of reasons one might want to use a Giant Octopus in lieu of the much higher level Kraken, there are a number of things to consider when deploying this majestic creature at your table.

Mechanically, as a Neutral aligned Aquatic Animal, the Giant Octopus is primarily suited to living underwater (as it cannot breathe air) and its stats reflect that. Notably, its land speed and swim speeds (15 and 40 feet, respectively) allow it to act tactically similar to how a Roc might in that it can deploy hit and run tactics against land-bound targets. This is emphasized particularly with Jet, an ability that allows the Giant Octopus to move five times its speed with a single action.

Compression, which allows the Giant Octopus to squeeze through a comparatively small space, can very easily be utilized in a number of story mechanics. Giant Octopi that have made a habit of stealing into impossibly small spaces can make them difficult to find even with a highly determined group of heroes. Consider utilizing its superior aquatic mobility in addition to its Writhing Arms and Constrict abilities to simply drown the ill-prepared. It may be an animal, but the real world octopus is a crafty creature and any combat you run should reflect that.

Do note that the Giant Octopus is ultimately an Animal, and it's not necessarily a creature prone to fighting to the death; running (swimming?) away is an option too! Between its various martial abilities and the Giant Octopus Venom/Ink Cloud, it can be a challenging foe for 4th to 7th level parties, in addition to a potentially strong animal ally for an aquatically oriented game.

Hook 1 (Max) - Ocean's Avenger

The coastal town of Gambler's Wharf has seen better days. No ship has arrived at nor departed from the port for the better part of last two months. Inquired as to what might be the reason, they only respond with some permutation of a 'beast from the deep.'

The aforementioned beast does not like the connotation, instead preferring to think of itself as the Ocean's Avenger. How or why the enormous octopus gained sentience is anyone's guess, though the fact remains that it is intent on wreaking havoc upon those who have for generations hunted its marine kin.
Knowing full well the weaponry deployed by land monsters to be superior, Ocean's Avenger armed itself with an armor comprised of the hulls of ships it has sank in addition to wielding weapons and improvised armaments in each of its tentacles such as masts or harpoons found at the seafloor. Although its hatred burns bright, the only thing it really wants is for land dwelling folk to leave its ocean dwelling brethren alone.

Hook 2 (Nemanja) - Inherited Infestation

In merfolk culture, large octopi are treated in a similar way humans and dwarves treat dogs - they are selectively bred for highly specialized roles that support their masters. There are agile octopi that hunt in small packs, massive, heavyset octopi that move and manipulate large amounts of all kinds of material, long tentacled octopi who scour nooks and crannies of underwater cities for lost items, and dozens more.

When the entire population of the underwater Metropolis of Sitnaltas vanishes overnight, hundreds of now masterless octopi end up infesting the entire eastern coast of Akonos.

Hook 3 (Reece) - Familiar Quarrel

The fact that octopi are more intelligent than other animals is well known. When a particularly clever octopus comes in contact with pact magic of some sort, the resulting familiar is doubly so, to the benefit (or more often chagrin) of the mage that it serves.

In the case of Magus Lethem Ganthix, Assistant Professor of Marine Studies at the University of An'Zar, he needs his familiar far more than it needs him. The son of a fisherman, Lethem has surprised the world of academia by publishing accurate, comprehensive works on marine life and the influence of the aquatic ley lines with little in the way of credentials or formal training. While he may be hesitant to answer questions in person, his writings from his secluded office are magnificent.

Faculty have caught Lethem deep in conversation within his office, which is always empty save for his octopus, staring back from its tank. Some have reported that these discussions have recently been devolving into arguments, with Lethem sounding increasingly distraught at the "credit" and "authorship" that spearhead them.