Wrath of the Drowned

Conjure the turbulent waters around your patron, creating a 15 foot radius sphere of murky water. Those entering the vicinity must make a CON save throw, and take 3d8 cold damage immediately from the frigid waters, and 3d8 necrotic - halved on a success - at the end of the enemy's turn. The sphere counts as difficult terrain for creatures without a swimming speed. As a reaction, if a creature ends it's turn within the sphere, the spirits can form the beast which sank their ship, grappling one creature inside. Using this feature again relinquishes any past grapples. The sphere counts as heavily obscured terrain.