Sea of Thieves is rolling out a wave of changes to the game with its fourth free expansion, Shrouded Spoils. This time, Rare is focusing on ways to revamp the game as opposed to adding new bosses or territory.

The most major feature of this update is Fog. Fog is a new emergent threat which will hinder visibility and hide threats in the distance. Captains ought to be prepared, because Fog’s going to add a huge sense of surprise to boss encounters.

To capitalize on the strengths of this new game mechanic, they’ve overhauled a few of the game’s bosses. The Kraken will now spawn for frequently and has a new attack pattern, the Kraken Slap. As for the Megalodon, the Megalodon’s character model is getting some visual tweaks. Both bosses will have new loot to earn.

There’s a few other neat changes to the game’s encounters. The developers have decided to give skeleton ships some love by giving them a major AI overhaul. When you find them roaming the seas, they’ll either be aggressive and hunt you down, or passively wait. Six more skeleton forts were added into the game to add some more variety.

Additionally, mermaid statues are now back. Upon being destroyed, they drop gems which can be redeemed for Merchant Alliance reputation and gold.

This patch will introduce some new Merchant Alliance items to go along with the changes. You can pick up a “Crate of Ancient Bone Dust” or a “Mega-Keg.” The Mega-Keg will be especially useful for blowing up galleons and skeletons.

New customization options are coming too. A limited time cosmetic ship and set – the Wailing Barnacle – will be available. This comes with new cannons, a capstan, and wheel.

Sea of Thieves is currently available on Xbox One and Windows. The update officially rolls out on November 28th.