Overview
The Beast of Bartle Bay is a low level encounter designed to just add some depth to the world around the players with minimal extra work. A nearby beach could be getting threatened by this creature, and the players hear a rumor of a creature that makes you feel as though you are drowning while on land.
Fight Synopsis
The Beast of Bartle Bay is a fairly straightforward fight, there aren't many tricks up its proverbial sleeves. By design, it's a short but hard hitting fight. You should utilize its ability to crowd control as a bonus action with Crushing Depths to your advantage, striking forward with its attack as a follow-up. Alternatively, use the Crashing Wave ability to create space on the battlefield.
Personality
The Beast is a savage creature, it doesn't have much in the way of planning and brute forces its way through everything. It likely will not tactically attack anyone, and will just assault the closest thing.
Brief Lore
There's a nursery rhyme everyone knows.
"Beware, beware
"Beware, beware
The Beast of Bartle bay
The coves its stomping ground
And if you feel
Its gaze upon your form
Run quick, leave no ground
For if it catches up to you
Its teeth and claws will tear
Flesh and bone be stripped from you
'Til your body is laid bare
Flesh and bone be stripped from you
'Til your body is laid bare
Beware beware
The Beast of Bartle Bay
Hailing from the sea
Incarnate spawn
Of crushing depths
Consuming all before its maw"
The Beast of Bartle Bay just started appearing one day. Think back to every movie involving a shark - everything is hunky dory, and then suddenly it isn't. Depending on how long this creature has been allowed to wander around, it may have created a nest and have all sorts of goodies in there. The beaches may be a ghost land. All things to consider while inserting the Beast into your game.
Music
The right music helps set the tone amazingly. For this encounter, that has a fast paced tempo and conveys some danger is what you're looking for. The Hunt Begins from The Witcher 3: Wild Hunt should do the trick!.
If you like this encounter, consider buying an encounter package here!